Prime Minister Stephen Harper says he "dismissed" chief of staff Nigel Wright over a $90,000 cheque that Wright gave to Senator Mike Duffy to cover Duffy's questionable expenses, contrary to Harper's previous comments that Wright resigned.

In a Halifax radio interview with Jordi Morgan on News 95.7, Harper said his responsibility in the ongoing Senate expenses scandal is to take "appropriate action."

"I think the responsibility whenever things go wrong is for us to take appropriate action. As you know, I had a chief of staff who made an inappropriate payment to Mr. Duffy, and he was dismissed," Harper said.

Senators are debating suspending Duffy, Patrick Brazeau and Pamela Wallin without pay or benefits. All three are being investigated by the RCMP for questionable claims over housing or travel expenses. Former Liberal senator Mac Harb, who resigned in August, is also under investigation for his housing claims.

None of the senators has been charged. Brazeau is facing unrelated charges in a separate criminal matter.

Audits by Deloitte found the Senate's rules for claiming housing and travel expenses to be unclear.

'Appropriate' for Senate to 'take action'

Harper named Brazeau, Duffy and Wallin to the Senate at the end of 2008. Duffy and Wallin were successful fundraisers for the Conservative Party, attending local riding events across the country.

Harper says he wants the Senate to take "appropriate" action.

"I think quite frankly all of us, both in the Senate and the rest of the government, we have been very very patient as these senators have been audited and all of the facts have been looked into," he said.

Senate government leader Claude Carignan seems to be open to a less stringent penalty than suspension without pay and benefits.

It's "clear," Harper said, that the three senators have "taken hundreds of thousands of dollars in inappropriate expenses," and he wants the Senate to take "disciplinary action."

"There has been a view in the Senate, a long historic view, and there's a few people who still believe it, even in our party, that the standard of sitting in the Senate is that you not have been convicted of a crime."

"So I think it's appropriate, as do a majority of our senators, that the Senate take action," Harper added. "We just say let the Senate vote and let the Senate's will be heard on this."

"I think if the Senate took action, the Senate would be showing some willingness to reform itself."