OTTAWA - The Commons ethics committee is urging a full-fledged public inquiry into the Mulroney-Schreiber affair -- but there's a split along party lines on how wide a mandate the new probe should have.

In a report tabled Wednesday, Liberal, Bloc Quebecois and NDP members called on Prime Minister Stephen Harper to make sure the rules are broad enough to follow the trail wherever it leads.

"To arbitrarily set fences around activities may restrict the commission's ability to deal with the evidence that it's undoubtedly going to receive,'' said Liberal committee chair Paul Szabo.

But Conservative backbenchers on the panel took a more restrictive view, arguing the inquiry should focus less on past events and more on strengthening ethical guidelines in future.

"We heard abundant contradictions at this committee,'' said Tory Russ Hiebert.

"But we didn't hear any evidence of wrongdoing by any public office holder. ... We have empty hands at this point on how this inquiry should proceed, except along the line we have recommended.''

The Tory minority report is strikingly similar to arguments put forward by Guy Pratte, the lawyer for former Conservative prime minister Brian Mulroney.

Pratte has claimed there shouldn't be an inquiry at all -- but if there is one it should be "forward-looking'' and concentrate on future reforms.

Hiebert insisted, however, that he and his backbench colleagues had no contact with Pratte or Mulroney on the subject, and any similarity in their views is purely coincidental.

He also noted that, in the end, it will be Harper's call on how to proceed. "We're not speaking for the government, we're not speaking for the prime minister.''

There was no immediate comment from the Prime Minister's Office, but Harper has repeatedly promised to call an inquiry once the ethics committee delivered a final report.

He has already asked his special adviser, legal scholar David Johnston, to present his own views on terms of reference for the probe by this Friday.

Mulroney has acknowledged accepting $225,000 from Schreiber to act as a lobbyist, after he left office, for a proposal to build German-designed light armoured vehicles in Canada for export.

The lobbying was to be aimed at foreign leaders whose countries might buy the vehicles, according to Mulroney.

Schreiber says the total payments were $300,000 and Mulroney was supposed to lobby the Canadian government -- something that could have put him in violation of federal ethics rules.

There has also been disagreement about Mulroney's attitude toward the armoured vehicle project while he was in power.

He has said he ordered his then-chief of staff, Norman Spector, to cancel an early version of the deal because it would cost the federal treasury too much.

But Fred Doucet, another former Mulroney aide who later signed on to lobby for Schreiber, said nobody told him the deal was off and he continued to meet with senior politicians and bureaucrats about it.

Johnston, in a preliminary assessment of the affair in January, suggested an inquiry could shed light on the financial transactions surrounding the armoured vehicle project.

Opposition MPs have called for a broader investigation that would include an earlier deal that saw Air Canada buy European-made Airbus jets while Mulroney was still in office.

Schreiber has testified that he mingled money from the various projects in his bank accounts, Szabo noted Wednesday.

"The inquiry is going to follow the money. If they find out that some of the money was intended for Airbus purposes, what are they supposed to do, ignore it?''

The opposition also wants a review of the $2.1-million libel settlement Mulroney reached with the Liberal government of Jean Chretien in 1998, when the full extent of his dealings with Schreiber had not come to light.

The Liberals want the issue to be examined as part of the public inquiry's work, but New Democrat MP Pat Martin says the Justice Department should take immediate action to recover the money from Mulroney.

"We don't have to wait until the end of a public inquiry to ask a court to set aside the settlement,'' said Martin. "That can be going on parallel to, and in conjunction with, a public inquiry.''