Liberal senators are trying to force key players in the scandal involving Sen. Mike Duffy鈥檚 expense repayment to testify before special parliamentary hearings.

Liberal Senate leader James Cowan argued before the Senate Tuesday night that a secret deal between Duffy and Prime Minister Stephen Harper鈥檚 chief of staff, Nigel Wright, may have violated the privileges of parliamentarians.

Wright stepped down on Sunday after CTV鈥檚 Ottawa Bureau Chief Robert Fife reported that he wrote a $90,000 personal cheque to help Duffy repay ineligible living expenses. Duffy also left the Conservative caucus over the growing scandal.

鈥淚f there was a connection, if monies were paid, which would influence the decision of a Senate committee, then that is contempt of Parliament and that infringes my privileges as a senator and it infringes privileges of senators, the Senate and interferes, I think, in a spectacular way鈥ith the independence of the Senate,鈥 Cowan told reporters Tuesday evening.

Cowan is arguing that the executive branch interfered in the proceedings of the Senate committee looking at Duffy's expense claims.

If Senate Speaker Noel Kinsella agrees that there was a breach of parliamentary privilege, he could send the issue to a special committee, which would be able to summon witnesses, including Wright.

Cowan suggested to reporters that the prime minister himself could be called as a witness.

Cowan鈥檚 motion to refer Duffy鈥檚 expense audit 鈥渢o the appropriate law enforcement agency鈥 was shot down. The audit will instead go back to the same Senate committee for another look.  

Former Liberal Senator Mac Harb also raised a question of privilege in the Senate on Tuesday, suggesting his reputation took a hit when the Senate committee ordered him to pay back $51,482 in improperly claimed living expenses.

Harb was also audited along with Duffy and former Conservative Senator Patrick Brazeau. Both Harb and Brazeau are fighting the orders to repay the money they claimed in living expenses.

Sen. Pamela Wallin鈥檚 travel expenses remain the subject of an ongoing audit. She also left the Conservative caucus amid the controversy.

Harb told the Senate that independent auditors found rules around primary residences were not clear, and they did not determine he had broken them.

Conservatives speak out on scandal

Earlier Tuesday, Conservative Sen. Jacques Demers said that senators who are caught abusing taxpayers鈥 dollars should do more than step down from caucus.

鈥淭hey should not be a senator,鈥 he said.

Demers made the comments after he attended a Conservative caucus meeting Tuesday morning.

Demers said, while all the facts have yet to emerge, Senators caught fleecing taxpayers should be out of a job.

鈥淚f he or she have done wrong and taken money that doesn鈥檛 belong to them they should be fired. That鈥檚 it. No independent. You鈥檙e out,鈥 Demers said.

Demers also said the expense scandal has given him pause to reflect. When asked what that meant, Demers said that if he doesn鈥檛 like what he hears once all the facts come out, 鈥淚鈥檓 going to go.鈥

Several Conservative MPs and Senators stopped to speak with reporters as they made their way into Tuesday morning鈥檚 meeting. While a number of MPs either refused to address the ongoing Senate expenses scandal or stuck to talking points, others expressed their disappointment.

鈥淢y constituents are not happy, my supporters are not happy, I am not happy,鈥 Foreign Affairs Minister John Baird said. 鈥淚 think what my constituents are telling me is that they want the Prime Minister to lay down the law. This type of behaviour is absolutely unacceptable.鈥

Heritage Minister James Moore said Canadians expect Parliamentarians and Senators to 鈥渞espect taxpayer dollars鈥 and anybody not doing that 鈥渟hould leave.鈥

When asked what his constituents are saying to him about the scandal and whether Duffy should resign, Moore replied:

鈥淚 think Canadians expect Members of Parliament and Senators to respect taxpayers鈥 dollars,鈥 Moore told reporters. 鈥淎nybody who鈥檚 here not respecting that commitment to Canadians, they should get out, they should leave.鈥

The Prime Minister鈥檚 Office insists that Harper did not know about the payout to Duffy or about any aspects of the secret arrangement.

When asked if the prime minister knew of the deal between Wright and Duffy, Moore said he didn鈥檛 know, but has been told 鈥渢hat鈥檚 not the case.鈥

Demers told reporters that there were many occasions when he was an NHL head coach that he didn鈥檛 know everything that was happening with his team. Demers said he trusts the prime minister.

鈥淭here鈥檚 a lot of things that were done behind my back as a coach and I didn鈥檛 know about it and I found out after the fact,鈥 Demers said. 鈥淚鈥檓 just saying I know Mr. Harper is an honest person.鈥

During Tuesday鈥檚 caucus meeting, Harper told Conservative senators and MPs, as well as reporters who were permitted to observe his opening remarks, that he is 鈥渘ot happy鈥 about the conduct of parliamentarians 鈥渁nd the conduct of my own office.鈥

He also suggested that anyone seeking to use their place in Parliament for their own benefit 鈥渟hould make other plans.鈥

With files from Andrea Janus and The Canadian Press