Michael Ferguson told a House of Commons committee Tuesday an independent body would make MPs more accountable and boost public confidence shaken by the Senate spending scandal.
Ferguson was testifying before the House affairs committee, which is reviewing the way spending in the Commons is monitored and audited.
Citing political spending scandals in Britain, Nova Scotia and Newfoundland and Labrador, he argued existing accountability on Parliament Hill is too weak and urged MPs to examine the fixes made in those and other jurisdictions.
Ferguson also offered to do the oversight himself, either as the official auditor for the House of Commons or in an advisory capacity.
He said his office could take on the responsibility without necessarily requiring more resources.
"I believe that independent audits and some form of oversight would strengthen members' accountability and enhance the public's confidence in the governance mechanisms of the House of Commons," Ferguson said in a statement.
His office was previously invited to audit on a one-time basis the financial administration of the House of Commons, which included reviewing a small sample of MPs' expense claims.
Ferguson's June 2012 report found a relatively high compliance rate: 98.5 per cent of claims examined were properly documented and appropriate. His parallel audit of the Senate's financial administration in 2012 found slightly a lower compliance rate, 94.8 per cent.
But Ferguson said Canadians need better assurances that parliamentarians are spending tax dollars properly, which is only possible when an independent body routinely polices the system rather than politicians themselves.
He pointed to the example of the Scottish parliament, where member expense claims are posted on the Internet along with receipts.
Canada's MPs currently post financial statements online that include only general categories, and without receipts.
The NDP has pressed to replace the current vetting body, the Board of Internal Economy made up of MPs , with something else.
Ferguson is currently auditing the living and travel claims of most senators, after being invited to do so by the Senate's internal economy committee.
The process is expected to take up 18 months, and three senators now being probed by RCMP for expense irregularities — Mike Duffy, Pamela Wallin and Patrick Brazeau — will not be included. Ferguson has not yet decided whether to issue interim reports.
Earlier this month, the Commons House affairs committee was told some 70,000 expense payments are made to MPs each fiscal year, and more than 4,000 so-called "regret letters" are sent indicating a problem with a claim.
Some parliamentarians have privately expressed concern about any detailed audit of their expense claims, in particular hospitality, for which an MP can spend up to $10,734 each year.
They argue that audit reports publicly identifying the recipient of hospitality may interfere with their proper role as a mediator between constituents and government.