Information released this week by the federal government has some opposition MPs thinking twice about testimony they heard a few months ago.

Public Safety Minister Vic Toews tabled a list of the experts serving on his firearms advisory committee Monday, in response to a written question from a Liberal MP.

The advisory committee includes several people who appeared before a parliamentary committee last fall to support government legislation to scrap the long-gun registry.

When Murray Grismer testified before the public safety committee last fall, the Saskatoon police officer made it clear he was appearing as an individual who supported the bill to abolish the long-gun registry.

"My comments here today are mine and mine alone," Grismer told MPs on the committee.

But according to the documents, Grismer and three others who appeared before the committee are members of the panel that provides advice and expertise to Toews, the minister responsible for the bill to scrap the registry.

Grismer and the others did not disclose their membership on the advisory panel to the MPs on the committee.

Grismer told CBC News Tuesday he didn't see a problem in appearing before the committee to express his personal point of view.

"I went there as an individual. I was asked to appear. I got a call from the clerk and had no direction from any member or the minister's office."

Simon Fraser University Prof. Gary Mauser is another member of the firearms advisory committee who testified in November. "I appeared as an individual. I was not sponsored by anyone. I did not represent any organization or my university or the government. I represented myself."

Opposition members on the public safety committee saw things differently.

"When you see a witness supposedly as an individual, with some individual point of view, who is actually an appointee of the government itself, there to bolster the government's position — and that's what they did — then I think that's wrong," the NDP's Jack Harris said Tuesday.

Liberal Francis Scarpaleggia said it was a matter of transparency, adding that committee members might have approached the witnesses in a more skeptical manner or asked different questions had their affiliation with the advisory panel been disclosed.

"That advisory council was stacked with individuals who are bent on eliminating the registry and other forms of gun control in Canada."

Scarpaleggia added that committee hearings are intended to bring in the public to offer a variety of opinions and technical expertise, "not ... as a tool for organizing one's supporters."

The government has on several occasions refused to provide an updated list of its firearms advisory committee, but the list tabled this week shows it remains much the same as it did back in 2006, one of the last times it was made public. Several of the members on the list make their affiliation known on their own websites.

Candace Hoeppner, parliamentary secretary to the public safety minister, said it's up to opposition members on the committee to do their research. "All they had to do was ask a few questions or be prepared, which it seems that they weren't."

Hoeppner said witnesses appear before Commons committees in various capacities.

"It's not at all uncommon for individuals who in their capacity advise ministers or the prime minister, they do so openly. And then they go and testify in their capacity — and I'll give you an example, the governor of the Bank of Canada, Mark Carney," she said.

Advisory panel members John Gayder and Linda Thom also appeared before the committee as individuals. Members Tony Bernardo, of the Canadian Shooting Sports Association, and Greg Farrant, of the Ontario Federation of Anglers and Hunters, also appeared as representatives of those organizations.

The other members of the federal advisory panel are Linda Baggaley, Steve Torino, Alain Cossette, Louis D'Amour, Gerry Gamble and Kerry Higgins.

Committee members are not paid, but the government covers their expenses. Information also tabled Monday shows that since January 2008, the committee has incurred travel costs of $19,863 and hospitality expenses of $4,238.

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• What does this new bill on the gun registry do?

  We keep hearing about scrapping the long-gun registry, but really what we're talking about is scrapping the requirement for people to register their rifles and shotguns - that's what Bill C-19 aims to do by making amendments to the Criminal Code and Firearms Act. Once passed, people will not have to register their non-restricted or non-prohibited firearms. It also provides for the destruction of existing records in the Canadian Firearms Registry for those firearms. <em>With files from CBC</em>

• What exactly is the registry?

  It's a centralized database overseen by the Royal Canadian Mounted Police that links firearms with their licensed owners. It contains information about all three types of guns that must be registered - non-restricted, restricted and prohibited. (All firearms must be registered.) To register a firearm, you have to have a licence to possess it.

• Does the bill make any changes to licensing requirements?

  No. Canadian residents need a licence in order to possess and register a firearm or ammunition and that won't change. There are a couple of different kinds of licences because of various changes to laws and regulations over the years.

• What are long guns?

  There are three types of guns under Canadian law: non-restricted, restricted and prohibited. Most common long guns - rifles and shotguns - are non-restricted but there are a few exceptions. A sawed-off shotgun, for example, is a prohibited firearm. A handgun is an example of a restricted firearm. Different regulations apply to different classifications of firearms.

• How many guns are we talking about?

  As of September 2011, there were about 7.8 million registered guns. Of those, 7.1 million are non-restricted firearms.

• Why does the government want to get rid of the long-gun registry?

  The government says it is wasteful and ineffective at reducing crime and targets law-abiding gun owners instead of criminals, who don't register their firearms.

• Who wants to keep it?

  Police and victims' groups are big supporters of the registry. Police say the database helps them evaluate a potential safety threat when they pull a vehicle over or are called to a residence. They also say it helps support police investigations because the registry can help determine if a gun was stolen, illegally imported, acquired or manufactured. This year, the RCMP says police agencies accessed it on average more than 17,000 times a day.

• When will the registry cease to exist?

  The government has passed the legislation and the registry no longer exists. Except for in Quebec, where an ongoing court challenge means the owners must still register their guns in the province.

• Why does the government want to destroy the records?

  The government is doing this to ensure that no future non-Conservative government can recreate the registry. Public Safety Minister Vic Toews has also made it clear that if any province wants to set up its own registry it would get no help from the federal government. The Conservatives are so fundamentally opposed to the existence of the records, because they say they focus on law-abiding citizens instead of criminals, that they don't want them available for anyone to use.

• How much does the registry cost?

  The registry cost more than $1 billion to set up in 1995 and the cost was the source of much controversy. Public Safety Minister Vic Toews said on Oct. 25 that the government's best estimate is that it costs about $22 million a year to operate. That's the entire registry, not just the long-gun portion, but he noted most of the guns in the registry are long guns. He said he didn't know how much money scrapping the requirement to register long guns would save the government. Conservative MP Candice Hoeppner says there are also "hidden costs" that are borne by provincial and municipal police agencies to enforce the registry.