The opposition is raising the heat on the Conservatives to cancel Karlheinz Schreiber's extradition order.

Liberal human rights critic Irwin Cotler told Â鶹´«Ã½net's Mike Duffy Live that an inquiry into the Mulroney-Schreiber affair will be put in jeopardy if Schreiber is sent back to Germany.

"For that public inquiry to proceed you need to have the main witness present otherwise the truth can't be pursued, (and) in the end justice cannot be served," said Cotler.

Cotler, a former justice minister, said that Canada can send Schreiber to Germany once he gives his testimony.

He also shot down the idea that Schreiber could testify by video from Germany. Cotler said that would not work because cross-examinations require a witness to be present in person.

Bloc Quebecois and New Democrats, like their Liberal counterparts, argued in the Commons Friday that Schreiber's extradition to Europe will jeopardize the inquiry.

"If Karlheinz Schreiber is deported on Dec. 1, we might as well cancel the whole public inquiry,'' said the NDP's Pat Martin.

Schreiber told the Canadian Press that it would be difficult for him to testify at an inquiry in Canada if he's in a German jail and facing criminal charges. The comments were more moderate than those from an earlier interview in which he told the Globe and Mail that he wouldn't say "one fu--ing word" if he's extradited.

Schreiber's comments follow an Ontario appeals court decision Thursday that paved the way for Schreiber's deportation to Germany where he is facing fraud, tax evasion, and bribery charges. The order was delayed for 14 days to give Schreiber a last shot at appeal to stay in Canada.

In Winnipeg, Justice Minister Rob Nicholson refused to say if he will postpone Schreiber's extradition.

Public Security Minister Stockwell Day told the Commons that Canada has to balance two separate interests. It has to honour an extradition deal with Germany and it has to have his testimony.

Day said the two sets of interests could be "complementary.''

"Within the guidelines of a full public inquiry is the power to subpoena, the power to require people to be witnesses, and that would take place wherever an individual may find themselves,'' Day said.

But a legal expert told Mike Duffy Live that bringing a witness back from another country is not guaranteed.

"It's one of those possession is nine-tenths of the law (situations)," said Lawrence Greenspon, a distinguished Ottawa defence lawyer.

"You hold on to something, if you think it's of value. We should keep him here and see what he's worth."

Schreiber has said in court documents that he paid Mulroney $300,000 in three separate cash payments shortly after Mulroney left office.

Schreiber has also alleged the two met to discuss business matters while Mulroney was still prime minister. The allegations have not been proven in court and Mulroney has denied the accusations.

In 1997, Germany issued an arrest warrant for Schreiber based on commissions he allegedly received on the sale of armoured vehicles to Saudi Arabia in 1991, the sale of helicopters to the Canadian Coast Guard in 1986, and the sale of Airbus jets to Canada in 1988.