But Sen. Carolyn Stewart Olsen insists she's been falsely accused of improperly claiming living expenses.
The Conservative senator — who is closely allied with Prime Minister Stephen Harper and who was instrumental in calling on the RCMP to investigate the allegedly invalid expense claims of four other senators — denies she wrongly claimed more than $4,000 in accommodation and meals at a time when she was not involved in any Senate business.
"I have reviewed these claims with the Senate finance administration and they have found nothing improper," Stewart Olsen said in a terse written statement Tuesday.
"I welcome the auditor general's review of all senators' expenses."
The statement followed a report in The Huffington Post Canada, which alleged that Stewart Olsen wrongly claimed daily living expenses from December 2010 to February 2011 — even though the Senate was not sitting for most of that time and her calendar showed no public business in Ottawa during that period.
The Huffington Post quotes Stewart Olsen as saying she shouldn't have claimed per diems for days when the Senate wasn't sitting and promising to repay the money if a mistake was made.
However, her subsequent statement made no mention of repayment or having erred. Stewart Olsen did not respond to a request for clarification.
Stewart Olsen was a key member of the Senate's internal economy committee, which sat in judgment on the dubious expense claims of four other senators — Mike Duffy, Pamela Wallin, Patrick Brazeau and Mac Harb.
She was one of three members of the steering committee which oversaw external audits into the quartet's expense claims and ultimately demanded repayment while recommending that the RCMP investigate.
Stewart Olsen and fellow Conservative Sen. David Tkachuk have also been accused of initially whitewashing a report on Duffy to essentially clear him of any deliberate wrongdoing.
They've denied those accusations but ultimately changed their tune on Duffy after it was revealed he'd accepted $90,000 from Harper's chief of staff, Nigel Wright, to reimburse the Senate for his invalid housing allowance claims. Wright resigned several days after news of the transaction leaked out.
Both New Democrats and Liberals called Tuesday for Stewart Olsen to be booted off the internal economy committee, at a minimum.
"How could she continue sitting there and look at these (invalid expenses) issues in the same Senate when she had been doing the same thing? It's unbelievable," said NDP Leader Tom Mulcair.
Liberal MP Marc Garneau said Stewart Olsen's credibility is "completely shot."
But Sen. Gerald Comeau, chair of the committee, said in an interview that he intends to first check with Senate finance officials to see if Stewart Olsen's expense claims were all valid. If so, he said there'd be no need to pursue the matter further.
There's nothing necessarily suspicious about claiming expenses on days when the Senate or its committees aren't sitting or when a senator has no public Senate business to attend to, Comeau said.
Senators often return to the capital to work in their Senate offices, consult with their staff, conduct research in the parliamentary library and so on, he noted.
"I've done it many times myself, actually going to Ottawa to do work which would be kind of impractical for me to do from my home (in Nova Scotia)."