The Conservative government showed signs of softening its sanctions against three disgraced senators late Tuesday with a proposal to allow them to keep their benefits if they are suspended for claiming expenses improperly.

It will be Friday at the earliest before the Senate votes on whether to suspend the senators without pay, ramping up the pressure on Prime Minister Stephen Harper as he prepares to deliver a key speech at the Conservative convention in Calgary.

The Senate Conservatives moved Tuesday to limit the debate on motions to suspend Pamela Wallin, Mike Duffy and Patrick Brazeau from the Red Chamber for alleged "gross misconduct" related to their expense claims. If they are successful, Friday afternoon will be the earliest the Conservatives can force votes on the three suspensions.

Story continues below advertisement

During Tuesday's late-night debate, the Conservative side of the Senate proposed that Mr. Duffy, Ms. Wallin and Mr. Brazeau would be able to keep their medical benefits even if they are suspended without pay.

The move was blocked by an independent senator, but could ‎be revived as negotiations to resolve the question of what to do with the three senators continue.

Mr. Duffy, who has a heart condition, and Ms. Wallin, who has had cancer, have both argued that suspensions without benefits would leave them vulnerable to their medical conditions.

Liberal senators argued against the move to limit debate, saying there is a risk the three senators will be punished without due process. The Liberals also asked the Speaker, Conservative Senator Noel Kinsella, to rule on whether the motion to limit debate was procedurally correct. The request could further delay the final votes, depending on which way the Speaker rules.

Claude Carignan, the government leader in the Senate, acknowledged Tuesday that the suspension votes are unlikely to occur before the Conservative convention gets under way Thursday night. "If the Liberals start to play with the adjournment and use [this] tactic, it's impossible," he said.

As long as the Senate continues to ponder what should be done with the three disgraced senators, "the government's agenda cannot move forward," Mr. Carignan said. "It is time to start moving on to other things."

If the suspension motions are passed on Friday, Mr. Harper will be able to tell members of the Conservative party that the matter has been dealt with when he gives a speech at the convention Friday night. If, however, the debate drags on until the following week, he may be forced to alter his message.

Story continues below advertisement

The Senate controversy is deeply troubling to the Conservatives and Mr. Harper, who appointed all three of the senators facing possible suspension. Facing more questions from the opposition in the House of Commons Tuesday, Mr. Harper heaped blame for the affair on his former chief of staff, Nigel Wright, who gave Mr. Duffy $90,000 to repay questionable housing expenses. Mr. Wright left the job after the arrangement was reported in the media.

The delay in votes on the Senate suspensions could mean some senators will have to cancel their plans to attend the Conservative convention.

Only about a third of Conservative senators had planned to attend the convention, a source said, in part because many felt they would not be welcomed by Conservative MPs who are frustrated with the ongoing expenses scandal. Senators were also told they should not bill the Senate for any convention-related expenses because of concern over the optics of doing so during the ongoing controversy.

Last week, Mr. Carignan signalled that he was willing to consider lighter punishments for the senators based on their comments in the Red Chamber. Sources familiar with the matter said Sunday that Mr. Carignan would not consider any changes to the motions that would allow the senators to continue to be paid. But the sources said there could be flexibility on the length of time senators were suspended or the conditions of the suspensions, such as medical and pension benefits.

However, Mr. Carignan indicated on Tuesday that he had no plans to amend the length of the suspensions. "Look, we asked for suspension without pay up to the end of the session. I think that what we have, actually, it's appropriate and it's what we [will] continue to fight for."

The Conservatives accused the Liberals of wasting time and trying to unnecessarily extend the debate, a point James Cowan, Liberal leader in the Senate, disputed. "We're not trying to drag this out," he said. "But these are very, very important principles and very important issues that we are dealing with, and I think Canadians realize how important they are and the question is, why are they doing it."