The Liberals are demanding a public inquiry into allegations of questionable cash payments to former prime minister Brian Mulroney. But the Tory government brushed aside calls for an inquiry.

"Will the prime minister take every step necessary regarding this disturbing information about Brian Mulroney to get to the bottom of this matter?" Liberal Leader Stephane Dion asked during question period on Thursday.

Dion continued: "The current prime minister owes the institution he represents a duty to shed full light on this issue. Will he do that? Will he set up a commission of public inquiry?"

Newly published reports say Mulroney waited years before paying taxes on $300,000 he received from German-Canadian Karlheinz Schreiber deal maker shortly after leaving office.

According to a report The Globe and Mail, Mulroney was delayed in paying the taxes because of a "cataclysmic event" in his life in November 1995.

The event refers to an RCMP letter to the Swiss government, which falsely accused him of a crime in the purchase of Airbus planes by Air Canada.

In 1997, the Chretien government was forced to apologize and pay Mulroney a $2.1 million settlement in a defamation suit.

On Thursday, government House Leader Peter Van Loan responded to Dion's line of questioning by asserting that the case was already "closed."

Van Loan accused the Liberals of trying to wage a political vendetta.

"That Liberal leader was part of a cabinet that had to pay 2 million dollars of taxpayers' money for falsely pursued allegations in exactly this case."

The Liberals say the new information warrants another look.

"Taxpayers' dollars are lining the pockets of Brian Mulroney. Canadians deserve answers. Will this Conservative government launch an inquiry?" Liberal MP Karen Redman asked.

The government House Leader said the Liberals had nothing then and they have nothing now.

"If they thought there was something to it, why did that party settle that lawsuit and pay out $2 million of taxpayers' money," Van Loan asked.

A statement issued by Mulroney's spokesperson points out that the RCMP, after years of investigation, failed to find any evidence to substantiate allegations of wrongdoing.

Schreiber is currently in a Canadian jail awaiting extradition to Germany on unrelated criminal charges.

Earlier this month, Schreiber lost his latest legal challenge to avoid deportation to Germany.

The Supreme Court of Canada declined to hear an appeal by Schreiber, 73, who has been fighting extradition since 1999.