An extradition hearing for the German-Canadian businessman who sparked a public inquiry into corruption charges dogging Brian Mulroney should not go ahead until after he testifies at the probe, political experts suggest.

Karlheinz Schreiber, whose extradition hearing is set to begin on Thursday, faces deportation to his native Germany to face tax, bribery and fraud charges.

'I can't conceive of Canada extraditing him with all this buzz in the political atmosphere.'—Norman Spector, former chief of staff to Brian Mulroney

But the feeling among the opposition parties in Ottawa is that Schreiber should stay, the CBC's Rosemary Barton reported Wednesday.

"Of course, he is a key player in all this and they do not want him returned to Germany," she said. "So they are hoping to press the justice minister to interfere and keep Schreiber in the country."

"We have a big problem here [if] … Karlheinz Schreiber, the man making all the accusations, is extradited to Germany to face those charges," Globe and Mail columnist Lawrence Martin told CBC News. "If the central witness in this whole public inquiry is gone, what kind of public inquiry would you have then if you only have sort of half the story coming out?"

Norman Spector, Mulroney's former chief of staff, agreed, calling Schreiber "the major beneficiary" of the public inquiry.

"I can't conceive of Canada extraditing him with all this buzz in the political atmosphere," he told CBC News from Victoria earlier this week.

The 73-year-old Schreiber has alleged in a signed affidavit that Mulroney never lived up to his part of a 1993 lobbying deal, in which it was apparently agreed he would pay Mulroney $300,000 in cash in exchange for help setting up a pasta franchise. The affidavit claims the two men struck the deal two days before the former prime minister officially left public office.

'Half the story'

Among the other allegations is that a Mulroney adviser asked Schreiber to transfer funds in connection with Air Canada's 1988 purchase of Airbus planes to a Mulroney lawyer based in Switzerland.

Under immense political pressure, Prime Minister Stephen Harper changed his earlier call for a preliminary review to assess whether to move ahead with an inquiry, and skipped ahead by announcing plans Tuesday for a full public inquiry. The inquiry will proceed after an independent third party analyst — to be named soon — makes recommendations for its parameters, Harper said.

Mulroney welcomed the public probe, telling a crowd of business leaders in Toronto on Tuesday night that he has "absolutely nothing to hide" and that a broad inquiry would only allow him the opportunity to finally clear his name.

Justice John Gomery, who led the inquiry into the Liberal sponsorship scandal, offered his advice to whomever takes up the task of heading up the Mulroney-Schreiber probe.

Gomery offers advice

Speaking to the CBC on Wednesday, he said the commissioner would be well advised to seek a "basket clause," which would ensure that the commissioner has free rein to inquire into evidence without finding himself or herself restricted by the terms of reference.

Such a clause would give the commissioner the authority to "go where it's necessary to go in light of what you've learned," Gomery explained.

Quebec Liberal MP Marlene Jennings said Wednesday she expected the as-yet-unnamed commissioner to have the same powers that Gomery had during his inquiry.

"Judge Gomery had full powers. Full access that was virtually unheard of prior to that, [including access] to PMO documents, to the Privy Council documents," Jennings said.

Highly politicized job

"We'd like to see if Mr. Harper's going to be as open and as transparent as possible with any documents that will shed full light on this issue."

Gomery said whoever heads the Mulroney-Schreiber probe faces a difficult job, given how politicized the issue has become.

"It's clear that each of the political parties will try to get some sort of an advantage in public opinion as a result of this inquiry," he said from Havelock, Ont.

"It's in the interest of the Conservatives, surely, to protect as much as possible the reputation of Mr. Mulroney because he's a former [Progressive] Conservative prime minister, and I guess it would be to the advantage of the Liberals to achieve the opposite result."