He noted that he was invited by the Senate to conduct the audit and has received no similar invitation from the Commons.
Nevertheless, he said a detailed audit of each MP's expenses isn't necessary to know that the Commons could benefit from the same recommendations he's made for senators on greater transparency and independent oversight of how they spend taxpayers' dollars.
"I think there's a lot here that they can learn from and that they should learn from," Ferguson told a news conference shortly after his audit report was tabled in the Senate.
"I think certainly the idea of considering whether they have sufficient transparency, considering whether they can show that there's independence and objectivity in the decisions that are made around spending, I think those are things the House of Commons should look at and consider as well."
At the moment, MPs' spending is policed by the board of internal economy, a secretive group of four Conservatives, two New Democrats and one Liberal MP who meet behind closed doors and typically issue only cursory summaries of their decisions.
The Senate has a similar internal committee of senators who have the final word on spending by their fellow senators. It is actually more transparent than the Commons equivalent, holding some of its meetings in public.
Ferguson said senators should not be policing themselves.
"(Senators) design their own rules; choose whether to enforce those rules, and determine what, if any, information will be publicly disclosed” and that, Ferguson said, "may give rise to a perceived lack of objectivity, as those individuals may be viewed as looking after their own interests."
The same situation applies to MPs.
Over the past five years, more than twice as many MPs have been accused of improperly spending more than four times the almost $1 million Ferguson concluded has been misspent by 30 senators.
The main opposition parties have proposed reforms to make MPs' spending more transparent and accountable.
The NDP has proposed replacing the board of internal economy with an independent oversight body while the Liberals have proposed opening up the board's meetings.
Although New Democrat MPs have recently sent mixed messages about scrutiny of their expenses, the NDP did call in a 2013 dissenting committee report for giving the auditor general a clear legislative mandate to audit spending in the House of Commons, including MPs' expenses.
Liberal Leader Justin Trudeau has proposed requiring performance audits of both houses of Parliament by the auditor general every three years and developing guidelines for when more in-depth, value-for-money audits should be conducted.
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