As the stench of impropriety wafts through the Senate, former auditor general Sheila Fraser says the only way to air out the Red Chamber is to open its books to full public scrutiny.

As things stand, the Senate conducts its own largely secret internal audits, and has only let the auditor general through its doors twice in its long history — the last time was Fraser in 2011 for a report presented to Parliament last year.

Now, instead of calling in the current auditor general, Michael Ferguson, to review the controversial travel expenses and housing allowance claims of four senators, the upper chamber enlisted the private accounting firm Deloitte Touche to take this on.

The difference is that the auditor general almost certainly would have made the results of his investigation public. The Senate may never reveal Deloitte's findings, despite Conservative Senate leader Marjory LeBreton's pledge Thursday to make public the "results of these investigations."

In an exclusive interview with CBC News, Fraser said that the auditor general should have full and permanent access to the books of both the Senate and the Commons to conduct the same "comprehensive audits" imposed on all federal departments and agencies.

"It is public money and not an insignificant amount of public money," Fraser says of the roughly $500 million Canadian taxpayers spend on MPs, senators and the operations of Parliament every year.

"While I believe the vast majority of people in both houses are honourable, there will always be a few who will try to circumvent the system."

An uphill battle

Fraser suggests that the auditor general conduct comprehensive audits of the Senate and Commons at least every 10 years, or more frequently if the spending watchdog smells possible trouble.

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Former auditor general Sheila Fraser: 'There should be accountability.' (Canadian Press)

"All these allegations are calling into question the reputation of the Senate," she argues. "So it goes beyond the individuals and really to the institutions."

Fraser's often scathing reports on government waste and mismanagement helped to make her one of Canada's most popular public servants of the past decade, before her retirement in 2011.

One of her final achievements was to pry open the books of the Senate, albeit just once, and with the promise that her audit would not include a comprehensive audit of senators' expense accounts.

Fraser retired in the early stages of the actual audit, and it was completed by Ferguson, her successor.

But Conservative Senator David Tkachuk, who chairs the Senate standing committee on internal economy, says the Red Chamber has no plans to call in Ferguson to settle the current expense account kerfuffle — and is not likely to do that for a long time, if ever.

Tkachuk says that after that 2011 review by the auditor general, senators "made a decision" that in future the Senate would conduct its own "random audits over the next number of years."

Tkachuk told reporters Thursday that the current review of travel and housing allowance claims, being carried out by the accounting firm Deloitte Touche, is the first of those random audits.

Earlier this week, however, Tkachuk appeared to say that the Deloitte auditors were called in only after some "very unusual" expense claims came to the attention of the Senate.

And interviews with numerous government and senate insiders suggest that random audits had little or nothing to do with exposing the expense account irregularities now under investigation by Deloitte.

Where do you live?

Under Senate rules, senators who live more than 100 kilometres from Ottawa are allowed to claim up to about $22,000 a year towards a secondary home in the capital to attend to their Senate duties.

Last fall, a media investigation reported that the principal residence being claimed by Patrick Brazeau, the Conservative senator currently facing criminal assault charges, was actually his father's home, which called into question his expense claims for a second house in the capital.

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Senator, and former TV journalist, Mike Duffy is having his housing expenses reviewed. (Canadian Press)

A few days later, questions were also raised about housing claims by Liberal Senator Mac Harb who has lived in Ottawa most of his life, including as a long-time MP and former deputy mayor of the city.

Harb's case was apparently reviewed by a special Senate subcommittee that was already investigating Brazeau's claim.

In January, the travel expenses and residency claims by Conservative Senator Pamela Wallin were allegedly flagged to a different senate committee.

At that point, the two committees decided to call in the private accounting firm Deloitte to take over all three cases.

Shortly after, the residency expense claims of Conservative Senator Mike Duffy came to the attention of one of the senate committees and was quickly added to Deloitte's investigation.

Value for money

So far, Tkachuk seems to be the only senator to raise the issue of random audits in all this.

But in any case, Fraser says internal financial audits are no substitute for the kind of work the auditor general does in a comprehensive review.

For one thing, financial audits only confirm that money has been spent as claimed — not whether the expenditure was justified, or whether taxpayers received maximum value for their money.

The former auditor general isn't at all surprised the Senate has once again bolted the doors to its accounting department.

For most of her 10 years in office, Fraser relentlessly hammered both MPs and senators over their refusal to subject themselves to the same scrutiny as other public servants entrusted with taxpayers' money.

"They will get into a large argument about how the members and their offices are distinct," Fraser says, "but it's still public money, and I think there should be accountability."

She adds, a possible understatement, "I think expectations of the public have certainly changed over the last 10 or 20 years."