The federal Conservatives are raising their own questions as the Liberals continue to hammer them over allegations they tried to bribe a cancer-stricken MP.

Independent MP Chuck Cadman's vote on May, 19, 2005, ensured Canadians did not have to head to the polls for a snap election.
(Canadian Press)

During question period Friday, the Opposition peppered the Conservatives with questions about an audio tape that suggests Stephen Harper knew about an offer to the late Chuck Cadman.

"In an interview taped in 2005, he was asked explicitly about the insurance offer. He did not deny it. In fact, he confirmed an offer was made," said Liberal House leader Ralph Goodale.

But the Conservatives are raising doubts about that tape, from an interview journalist Tom Zytaruk did with Harper after Cadman, an Independent MP from B.C., died in July 2005.

Conservative MP James Moore suggested it may have been edited.

"We've only of course seen a segment of the conversation and we want to see a full unedited version of this conversation," he told reporters.

In Zytaruk's forthcoming biography of Cadman, Dona Cadman claims two Conservative agents met with her husband two days before the vote and offered him a million-dollar life insurance policy in exchange for his support.

Zytaruk questioned Harper about the alleged offer of a life insurance policy in exchange for a vote that would topple the Liberal government of the day.

"I don't know the details. I know that there were discussions," Harper says on the tape.

Later, he explains the offer to Cadman was "only to replace financial considerations he might lose due to an election" and it was carried out by people who were "legitimately representing the party."

"It looks like a tacit admission that a bribe was made," Liberal MP Mark Holland said in the House of Commons Friday.

Cadman, an Independent MP, was dying of skin cancer when the crucial vote came up in the House on May 19, 2005. He sided with the Liberals, propping up the government and ensuring there was no summer election.

According to the rules of his government life insurance policy, his benefits — the amount of money his widow would collect — would be cut in half if he was no longer a sitting MP.

Conservative MP James Moore continued on Friday to deny any wrongdoing, even stating that Cadman himself said in two separate TV interviews that no offers had been made.

But Liberal MP Garth Turner suggested the clock was ticking on the Conservatives.

"If this story is not discredited substantially in the next 48 hours, then I am sure that a number of my colleagues will be very keen come Monday to pull the plug on this government," Turner said.

Just days ago, the Liberals pledged to allow the Conservative budget to pass in order to prevent a snap election.

Ethics committee to consider review

On Tuesday, the House ethics committee will look at three motions proposing to study the allegations that the Conservatives tried to buy Cadman's vote.

"I can pretty much guarantee that that will become an item of study for us," NDP committee member Pat Martin told CBC News on Friday.

The Liberals have also asked the RCMP to investigate.