Prime Minister Stephen Harper was hammered by the leader of the Opposition on Thursday during question period about what he knew about a $90,000 cheque to embattled Senator Mike Duffy, after saying that "very few people" knew about the deal.

Previously, Harper has said nobody knew about the reimbursement scheme between Duffy and Nigel Wright, who resigned as the prime minister's chief of staff after the existence of the personal cheque was revealed.

Harper changed his tune Thursday, saying Wright "informed very few people" — all of them known to be key confidantes.

"Mr. Speaker, I refer the prime minister to Hansard of June 5," said NDP Leader Tom Mulcair in question period on Thursday. "There was no 'very few' in there. It was 'nobody."'

On Friday, the Senate will resume debating motions to suspend Duffy, along with Senators Pamela Wallin and Patrick Brazeau, without pay or benefits for inappropriately claiming expenses. 

The government leader in the Senate, Claude Carignan, said a day earlier that there would be no Conservative Senate caucus on Friday, and that the Senate will resume sitting at 9 a.m. ET.  A vote on some motions is possible.

Duffy and Brazeau, along with retired Liberal senator Mac Harb, are under investigation by the RCMP for allegedly fraudulently claiming Senate housing allowances and living expenses.

The Mounties are also investigating the fact Duffy accepted $90,000 from Wright to help pay his expenses.

Suspension reveals Tory dissent

The debate over whether to suspend the three senators has revealed some dissent among Conservatives in the upper chamber as some have expressed their reluctance to pursue such action. 

Senator Don Plett, the former president of the Conservative Party, said doing so would set a precedent that could allow the Senate to suspend any senator who is an "irritant."

"We would be finding these senators guilty before giving them a fair trial," he said Thursday.

Plett's position echoes that of fellow Conservative Hugh Segal, although Segal's attempt to have the motions dismissed because of lack of due process and fairness was disallowed by the Senate speaker. 

Segal, his voice rising, accused the Senate of "committing professional capital punishment on our colleagues." Adding that he believes the Senate has the power to discipline senators, Segal questioned whether it has to take action that is "mean, arbitrary and cruel."

With files from The Canadian Press