The long-awaited bill that would put cellphone users "in the driver's seat" will be introduced next week, she said.
If passed, it would require that contracts be written in plain language and that they outline which services come with the basic fee and which services would cost more, she said.
It would also cap contract cancellation charges at $50 and require consent from cellphone users before their fixed-term contracts are changed.
"This is front and centre in the minds of Ontarians," said MacCharles. "We all have cellphones, some of us have multiple cellphone in our purses. So it's really time to do it."
Canada's telecommunications regulator is putting together a proposed code of conduct for the wireless industry, which may contain some of the same provisions, MacCharles said.
The Canadian Radio-television and Telecommunication Commission has already heard many complaints from cellphone users who feel they're being held hostage by three-year contracts.
But the rules proposed by the CRTC would be an "individual complaint code" that won't have the kind of enforcement mechanism the province has, she added.
"Four other provinces in Canada already have their own provincial legislation on wireless contracts," she said.
But the Canadian Wireless Telecommunications Association said Ontario should wait to review the new code before moving ahead with its own rules.
"Much of what the Ontario government is proposing is already common practice by wireless service providers," spokesman Marc Choma said in a statement.
"A national code from the CRTC would apply to all Canadians and supersede Ontario's proposed bill, making it irrelevant in any case."
The Liberals brought in similar legislation almost a year ago, but the bill died when the legislature was prorogued last October. Cabinet minister David Orazietti also introduced several private member's bills on wireless contracts when he was still a backbencher.
The minority Liberals need at least one other party onside for the bill to pass, but they say they've received support in the past from both the Progressive Conservatives and New Democrats.
NDP Leader Andrea Horwath said she wants to see the legislation before making a decision.
"There's lots of people who get led down the garden path with these contracts," she said.
"Unfortunately they're being led down the garden path by the Liberals, because this is the fourth time that they've brought forward legislation."
It's unfortunate that it's taken so long, said Conservative critic Jim McDonell.
"We're looking at the CRTC moving on a code sometime in the next few months," he said. "But if that doesn't go ahead, we need something to protect the people of Ontario."
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