After much anticipation and a rather long wait, Auditor General Michael Ferguson's office is ready to report on the previously secret spending habits of Canada's Parliament.

Two reports – titled “Administration of the Senate of Canada” and “Administration of the House of Commons of Canada" – are set to be tabled following each chamber's respective question periods on Wednesday.

The reports result from a much-anticipated probe started by Ferguson's predecessor, Sheila Fraser, who asked back in June 2009 to conduct a "performance audit" on $533 million of annual spending by both the House of Commons and Senate.

Parliament's books had not been audited since 1991, when only a sample of the expenditures was examined.

At first, Parliament's secretive all-party Board of Internal Economy said the proposed audit "would go beyond the scope of the auditor general's mandate" and turned Fraser down 10 months after receiving her request.

The Board of Internal Economy sets the rules for MPs' expenses, worth about $170 million a year, and also decides how to spend more than $330 million on the administration of the House of Commons. It is chaired by the Speaker of the House of Commons, and currently includes six MPs: three Conservatives, two New Democrats and one Liberal.

When the controversy erupted in 2010, only the Bloc Québécois came out in favour of letting Fraser see Parliament's books, although some MPs as individuals also favoured the additional transparency – including former Liberal Michelle Simson, who proactively disclosed the details of her office's expenditures and encouraged others to do the same.

A public outcry ensued and the board eventually relented, with two board members – Conservative Jay Hill and Liberal Marcel Proulx, neither of whom are still MPs – appearing with Fraser at a news conference in June 2010 to announce the audit.

Individual cases not anticipated focus of probe

A performance audit is not the same thing as a forensic audit, which would have been much more detailed.

Fraser stressed back in 2010 that performance audits only examine existing management practices, controls and reporting systems. The auditor general's office did not anticipate probing the management of individual member's offices or the merits of their transactions.

Former auditor general Sheila Fraser, seen here while still serving in February 2011, tried to soothe Parliamentarians' fears that the kind of performance audit her office proposed would not be probing a "$4 cup of coffee." (Pawel Dwulit/Canadian Press)

"Nor will we comment on the performance of the House, its committees, or individual members," she told reporters. "We are not going to mention individual cases," Fraser said in 2010.

Similar audits of politicians' expenses in Britain and Nova Scotia sparked scandals and police investigations.

At the time, Prime Minister Stephen Harper was said to be generally supportive of the audit, moving towards greater transparency around Parliament's spending practices.

While the audit may discover inappropriate spending — as happened in Britain — the performance audit is expected to focus on what spending rules are in place and if they are being followed.

"I've heard people talking about a $4 cup of coffee. I've got, quite frankly, better things to do than look for $4 cups of coffee," Fraser said at the time.

Before this probe, the expenses of Parliament were audited only by the private accounting firm KPMG. Only the broad outlines of the expenses are made public. The details aren't disclosed.

Allegations about individual cases of alleged misspending do occasionally surface. In February, former Bloc Québécois Leader Gilles Duceppe was called before the Board of Internal Economy after media reports alleged he used parliamentary funds to pay for a staffer doing partisan work.

The release of the auditor general's reports on Wednesday afternoon coincides with the anticipated climax of Commons debate over the controversial budget implementation bill. MPs are expected to plunge into a marathon set of amendment votes overnight and continuing through Thursday.