Finance Minister Jim Flaherty thanked Canada's banks on Friday for not lowering mortgage rates to match BMO's recently announced rock-bottom offer.

The minister had warned Canada’s lenders last week against launching a new mortgage war, after BMO brought back its 2.99 per cent rate for a five-year fixed term mortgage.

But it seems mortgage lenders (and even the big banks themselves) aren’t actually listening to Flaherty, as a growing number of brokers are dropping their rates to below even that of BMO.

And while that may be good for prospective home-buyers, it could prove in the long term to be bad news for Canada’s economy. With household debt already at sky-high record rates, further increases in mortgage debt could prove unsustainable.

In just the past several days, the number of lenders offering rates below three per cent, as advertised on the RateHub website, has just about doubled.

None of those lenders are the major banks; of them, only TD Bank has come close to matching BMO’s rate with a 3.19 per cent offer for a five-year fixed mortgage.

But what banks officially advertise and what they offer you when you walk through the door can be two different things.

Most banks aren’t advertising 2.99 per cent, but I know if you walk into any branch in the city [of Toronto] right now they’ll start off with 2.99 per cent as the starting rate,” mortgage broker Christopher Molder told The Globe and Mail.

In a sense, the previous mortgage war -- started in early 2012 by BMO -- never really ended.

Such rock-bottom rates are becoming commonplace,” the RateSupermarket blog reports. “With a buyer pool shrunk by CMHC mortgage rule changes, and softening sales nationwide, lenders have been playing the ‘how low can you go?’ game for some time now.”

RateSupermarket notes that Butler Mortgages is offering a 2.77 per cent mortgage in Ontario, and "broker-offered rates below 2.8 per cent have become the norm."

It’s precisely the “how low can you go” game that Flaherty warned financial institutions against last week.

My expectation is that banks will engage in prudent lending – not the type of ‘race to the bottom’ practices that led to a mortgage crisis in the United States,” Flaherty said, as quoted at The Globe and Mail.

That's a pretty clear indication that Flaherty is worried Canada could be following the U.S. down the path of irresponsible lending.

At the heart of the problem are two interrelated issues: Household debt and overpriced housing.

Fitch Ratings Agency recently estimated that Canada’s housing market is overvalued by 20 per cent. That’s somewhere in between TD Bank's estimate of a 10-per-cent overvaluation in the market, and Capital Economics’ estimate that housing costs are 25 per cent above fair value.

The falling mortgage rates ... threaten to undo Flaherty’s controversial efforts last summer to gradually let the hot air out of the housing market by tightening rules for government-backed mortgages,” Chris Sorensen wrote at Maclean's.

With rock-bottom mortgage rates, house prices could now push even higher, which in turn could set the housing market up for an even bigger correction if and when the time comes.

And with household debt at a record 164 per cent of household income, Canadians on the whole have little room to take on more.

At these house price levels, even a small increase in interest rates could sink many homeowners.

According to a survey carried out in the fall of 2011 for the Canadian Association of Accredited Mortgage Professionals, a one-per-cent interest rate hike could make mortgage payments unaffordable for 11 per cent of mortgage holders. A two-per-cent hike could sink 21 per cent of mortgage holders.

But that's a warning bell to which many in the industry simply aren't listening.

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  • Calgary: 3-bedroom house

    <strong>$1.08 million:</strong> Located in the trendy Altadore neighbourhood of Calgary, this as-yet-unbuilt modernist house features views of the downtown core as well as a personal elevator. Source: Keller Williams Realty

  • Calgary: 3-bedroom house

    <strong>$1.08 million:</strong> Located in the trendy Altadore neighbourhood of Calgary, this as-yet-unbuilt modernist house features views of the downtown core as well as a personal elevator. Source: Keller Williams Realty

  • Calgary: 3-bedroom house

    <strong>$1.08 million:</strong> Located in the trendy Altadore neighbourhood of Calgary, this as-yet-unbuilt modernist house features views of the downtown core as well as a personal elevator. Source: Keller Williams Realty

  • Toronto: 1-bedroom condo

    <strong>$988,000:</strong> Located in the posh Residences of the Ritz Carlton, in the heart of Toronto, this condo features one of only a handful of private terraces in the entire building. Source: Sotheby's International

  • Toronto: 1-bedroom condo

    <strong>$988,000:</strong> Located in the posh Residences of the Ritz Carlton, in the heart of Toronto, this condo features one of only a handful of private terraces in the entire building. Source: Sotheby's International

  • Toronto: 1-bedroom condo

    <strong>$988,000:</strong> Located in the posh Residences of the Ritz Carlton, in the heart of Toronto, this condo features one of only a handful of private terraces in the entire building. Source: Sotheby's International

  • Montreal: 4-bedroom rowhouse

    <strong>$998,000:</strong> This historic townhouse in the wealthy enclave of Westmount is "of historic interest," according to the realtor, and features its original glass doors and marble panels at the entrance. Source: Sotheby's International

  • Montreal: 4-bedroom rowhouse

    <strong>$998,000:</strong> This historic townhouse in the wealthy enclave of Westmount is "of historic interest," according to the realtor, and features its original glass doors and marble panels at the entrance. Source: Sotheby's International

  • Montreal: 4-bedroom rowhouse

    <strong>$998,000:</strong> This historic townhouse in the wealthy enclave of Westmount is "of historic interest," according to the realtor, and features its original glass doors and marble panels at the entrance. Source: Sotheby's International

  • West Vancouver: 1-bedroom condo

    <strong>$985,000:</strong> The real estate agent boasts that this property offers a "spectacular 180 degree view of the city, Lions Gate Bridge, Stanley Park, Kitsilano, Point Grey and beyond to Vancouver Island." Source: Angell Hasman Realty

  • West Vancouver: 1-bedroom condo

    <strong>$985,000:</strong> The real estate agent boasts that this property offers a "spectacular 180 degree view of the city, Lions Gate Bridge, Stanley Park, Kitsilano, Point Grey and beyond to Vancouver Island." Source: Angell Hasman Realty

  • West Vancouver: 1-bedroom condo

    <strong>$985,000:</strong> The real estate agent boasts that this property offers a "spectacular 180 degree view of the city, Lions Gate Bridge, Stanley Park, Kitsilano, Point Grey and beyond to Vancouver Island." Source: Angell Hasman Realty

  • Charlottetown, P.E.I.: 8-bedroom house

    <strong>$998,700:</strong> This historic property was once the Edenhurst Inn and is now on sale as a private residence. "No expense was spared in the construction of this home using sycamore and oak for interior finishing," the realtor says. Source: Re/Max Charlottetown

  • Charlottetown, P.E.I.: 8-bedroom house

    <strong>$998,700:</strong> This historic property was once the Edenhurst Inn and is now on sale as a private residence. "No expense was spared in the construction of this home using sycamore and oak for interior finishing," the realtor says. Source: Re/Max Charlottetown

  • Charlottetown, P.E.I.: 8-bedroom house

    <strong>$998,700:</strong> This historic property was once the Edenhurst Inn and is now on sale as a private residence. "No expense was spared in the construction of this home using sycamore and oak for interior finishing," the realtor says. Source: Re/Max Charlottetown

  • Winnipeg: 4-bedroom house

    <strong>$989,900:</strong> This modernist mansion from custom home designers Artista Homes features three fireplaces, including a three-sided one, and ensuite bathrooms with heated floors. Source: Royal LePage Alliance

  • Winnipeg: 4-bedroom house

    <strong>$989,900:</strong> This modernist mansion from custom home designers Artista Homes features three fireplaces, including a three-sided one, and ensuite bathrooms with heated floors. Source: Royal LePage Alliance

  • Kamloops, B.C.: 2-bedroom ranch house

    <strong>$960,000:</strong> This ranch house inspired by the "pueblo" style of the U.S. southwest is located in one of the few places in Canada that look like the southwest U.S. — the B.C. interior. The house features foot-thick concrete walls, and is set into the hillside to look half-buried. Source: Royal LePage Kamloops

  • Kamloops, B.C.: 2-bedroom ranch house

    <strong>$960,000:</strong> This ranch house inspired by the "pueblo" style of the U.S. southwest is located in one of the few places in Canada that look like the southwest U.S. — the B.C. interior. The house features foot-thick concrete walls, and is set into the hillside to look half-buried. Source: Royal LePage Kamloops

  • Kamloops, B.C.: 2-bedroom ranch house

    <strong>$960,000:</strong> This ranch house inspired by the "pueblo" style of the U.S. southwest is located in one of the few places in Canada that look like the southwest U.S. — the B.C. interior. The house features foot-thick concrete walls, and is set into the hillside to look half-buried. Source: Royal LePage Kamloops

  • Montreal: 5-bedroom townhouse

    <strong>$985,000:</strong> The realtor humbly describes this property as a "cottage in Westmount," but with five bedrooms, four baths and parking for two, this "cottage" is pretty out-sized. Source: Profusion Realty

  • Montreal: 5-bedroom townhouse

    <strong>$985,000:</strong> The realtor humbly describes this property as a "cottage in Westmount," but with five bedrooms, four baths and parking for two, this "cottage" is pretty out-sized. Source: Profusion Realty

  • Montreal: 5-bedroom townhouse

    <strong>$985,000:</strong> The realtor humbly describes this property as a "cottage in Westmount," but with five bedrooms, four baths and parking for two, this "cottage" is pretty out-sized. Source: Profusion Realty

  • Toronto: 4-bedroom bungalow

    <strong>$989,000:</strong> Located in an area with lots of surrounding commercial properties, the seller notes that the zoning could easily be changed to allow for a business. But you can always just live in this property, if paying $1 million for a bungalow strikes you as reasonable. Source: Realty Way Corporation

  • Saskatoon: 3-bedroom house

    <strong>$970,000:</strong> Don't let your eyes deceive you: This isn't a historic property. Rather, this duplex is a recreation of the Todd House, a 19th-century home located in Toronto. It's so modern it even features an indoor garage. Source: Hallmark Realty

  • Saskatoon: 3-bedroom house

    <strong>$970,000:</strong> Don't let your eyes deceive you: This isn't a historic property. Rather, this duplex is a recreation of the Todd House, a 19th-century home located in Toronto. It's so modern it even features an indoor garage. Source: Hallmark Realty

  • Saskatoon: 3-bedroom house

    <strong>$970,000:</strong> Don't let your eyes deceive you: This isn't a historic property. Rather, this duplex is a recreation of the Todd House, a 19th-century home located in Toronto. It's so modern it even features an indoor garage. Source: Hallmark Realty

  • Port Medway, N.S.: 3-bedroom seaside estate

    <strong>$990,000:</strong> Originally meant to be occupied by the architect who designed this property, this property on Nova Scotia's South Shore is "designed to be self-sustaining," the realtor says, and was built partly using reclaimed and re-purposed materials. Source: Tradewinds Realty

  • Port Medway, N.S.: 3-bedroom seaside estate

    <strong>$990,000:</strong> Originally meant to be occupied by the architect who designed this property, this property on Nova Scotia's South Shore is "designed to be self-sustaining," the realtor says, and was built partly using reclaimed and re-purposed materials. Source: Tradewinds Realty

  • Port Medway, N.S.: 3-bedroom seaside estate

    <strong>$990,000:</strong> Originally meant to be occupied by the architect who designed this property, this property on Nova Scotia's South Shore is "designed to be self-sustaining," the realtor says, and was built partly using reclaimed and re-purposed materials. Source: Tradewinds Realty

  • An actual house in Vancouver!

    It may be a shock to some, but yes, it is possible to buy an actual house — not a condo — for under a million in Vancouver. Here's proof: A two-bedroom property in the city's desirable Kitsilano neighbourhood, for a mere <strong>$998,800!</strong> Source: Sutton Group - West Coast

  • An actual house in Vancouver!

    It may be a shock to some, but yes, it is possible to buy an actual house — not a condo — for under a million in Vancouver. Here's proof: A two-bedroom property in the city's desirable Kitsilano neighbourhood, for a mere <strong>$998,800!</strong> Source: Sutton Group - West Coast

  • An actual house in Vancouver!

    It may be a shock to some, but yes, it is possible to buy an actual house — not a condo — for under a million in Vancouver. Here's proof: A two-bedroom property in the city's desirable Kitsilano neighbourhood, for a mere <strong>$998,800!</strong> Source: Sutton Group - West Coast