OTTAWA - A judge has rejected Brian Mulroney's request for a delayed start to hearings into his business dealings with arms dealer Karlheinz Schreiber.

Justice Jeffrey Oliphant ruled that commission hearings will begin as scheduled on March 30, not April 14 as Mulroney's lawyers had wanted.

The former prime minister requested a postponement so that Oliphant might clarify some ground rules.

Mulroney wants the investigation to focus primarily on his time in office, and not on his dealings with Schreiber upon his retirement from politics in 1993.

Oliphant will hear from Mulroney's lawyers again Tuesday. They will argue the judge has a duty to explain -- before the commission starts -- what elements of Mulroney's business dealings he will be probing.

The judge will take two days to consider that request and will issue his response in a verbal presentation Thursday.

Commission officials cast the latest ruling against Mulroney as a compromise, announcing there will only be two hearing days on March 30 and 31 before a two-week pause.

Mulroney has acknowledged he accepted $225,000 from Schreiber after he stepped down as prime minister to promote the building of German-designed light armoured vehicles in Canada.

He says he tried to line up support among foreign political leaders whose countries might buy the vehicles.

Schreiber says the deal was struck before Mulroney left office although the cash didn't change hands until later. He also claims the payments totalled $300,000 and that Mulroney was supposed to lobby the Canadian government, not foreign leaders.

The probe is expected to cost more than $14 million. Oliphant is to deliver a final report by Dec. 31, 25 months after Prime Minister Stephen Harper first promised an inquiry into the affair.