The Conservative government's leader in the Senate called on Liberals to support the move.
LeBreton told CBC News on Monday that auditors could look at every single dollar spent in the Senate, and said she expects Auditor General Michael Fergsuon would want to take a good look at the details of each senator's expenses.
But she said the final details of who and how far back that would go would be up to the auditors to decide.
"The auditor general is like most other Canadian taxpayers, he has been watching all of this I am sure. So, by asking an outside, respected body like the Office of the Auditor General, I would expect that when the motion calls for a comprehensive audit, that's exacly what they will do," LeBreton said.
Senate Opposition leader James Cowan told CBC News Monday he was not consulted on LeBreton's plan and wants more details, but said he was open to the idea.
Cowan said Liberal senators were open to "reasonable measures," but also noted that such a move can't really be done in one chamber and not the other, referring to MPs in the House of Commons.
"Is this just another attempt to change the channel here?" Cowan said in an interview. "The problem isn't in the rules and policies. The problem is in people who want to scam the system. That's the problem."
LeBreton's move follows efforts to toughen the rules about Senate travel and expenses and will put the whole chamber under scrutiny.
It's the latest Conservative effort to damp down a spreading scandal, which has become a staple of question period in the House of Commons.
Ethics watchdogs investigating
Ethics officers are in the process of investigating expense claims from several senators.
The Senate tabled reports on May 9 into expense audits conducted on four senators, including Senator Mike Duffy. At that time, LeBreton declared the matter "closed."
But the matter exploded when Nigel Wright, the prime minister's chief of staff, acknowledged he gave Duffy $90,000 to repay his ineligible claims.
Wright resigned over the unusual gift, but that just prompted even tougher questions from the NDP and Liberals.
- David Cochrane: What changed when the auditor general in Newfoundland and Labrador examined legislators' expense claims?
The Senate has voted to refer Duffy's case to the RCMP and questions have been raised about other dubious expense claims filed by Duffy.
The Senate has already done away with the old honour system that allowed senators to claim expenses without supporting documents.
Now the auditor general is being asked to review the whole mess.
"Canadians deserve to know at all times that their tax dollars are being spent wisely and in accordance with the law," LeBreton said in a statement.
AG examined random sample in 2012
In 2012, the auditor general did look at the Senate's "policies and control systems" for managing its operations and ultimately recommended the Senate require more documentation for senators' expense claims.
But those findings were based on a small, random sample of "transactions" by a few senators. Ferguson did not audit senators' expenses or their offices. LeBreton's proposal now is intended to offer the auditor a broader scope.
The Senate's internal economy committee "put some fences around what (Ferguson) could and could not do" last time, LeBreton said. "I actually don't think that's proper. The auditor general should go where he wants to go."
It's not clear if LeBreton's proposal means that each individual senator's expenses would be audited. She acknowledged a comprehensive audit could reveal an even bigger scandal over expense claims by senators.
Ferguson's office has not yet received a formal request for an audit, but says such a request from the Senate would be "uncommon" and without a set process for proceeding.
Meanwhile, Conservative MP John Williamson, a former communications director for Harper, introduced a private member's bill Monday that would strip the parliamentary pension from any MP or senator convicted of a crime punishable by a maximum penalty of two years in prison.
"At the end of the day, there is always going to be some level of the honour system and individuals have to play by the rules and, if they don't, I think the penalty, one of the penalties should be losing one's pension going forward," Williamson said.