The public safety minister is standing behind the whopping $1.1 billion security bill for the upcoming G8 and G20 summits, and says the auditor general is free to review the expenditures after world leaders go home.

The federal government has been under fire since it revealed it was setting aside $933 million to police the two events based on a so-called "medium-level threat assessment." Days later, the cost rose by $160 million to $1.1 billion, with further increases possible.

Vic Toews defended the bill Sunday, saying it was largely based on the fact the two summits are being held back-to-back, as well as on increased security concerns after 9-11 and the attempted bombing of a U.S. airliner last Christmas.

"I can assure you they're real costs, and I believe that they are justifiable," Toews told CTV's Question Period.

"It costs a lot to showcase Canada," he added. "It costs a lot to bring heads of state to Canada."

Toews scoffed at critics who say the bill is considerably higher than the $30 million London spent when it hosted the G20 summit in April 2009, or the $18 million spent by Pittsburgh in September 2009.

He called those estimates "nonsense," and said the numbers reflect each city's costs, not the federal government's bill.

"What we're comparing with is the national costs of running the G8 and the G20, and I've never seen any indication of what the national costs were for the United States or Great Britain," Toews said.

Toews said he would "welcome the auditor general reviewing" the summits' security bill, but also promised to release a detailed breakdown of the costs after the summits are over.

Auditor General Sheila Fraser said she would likely look into the summit spending "to see if it was done appropriately."

When asked if she was astounded by the high estimate, Fraser replied that "it certainly seems like a lot of money."

"All I've read is the media reports, and I would expect that there are a lot of people involved in this," Fraser told Question Period. "The costs of housing and overtime and equipment I'm sure are going to be substantial. So we would have to look at what planning has gone on and was the spending really just for these events or not."

Last week, Liberal MP Mark Holland formally wrote to Fraser to ask her to audit the security bill, which he called "the result of improper planning and foresight."

Toews said he would welcome any opportunity before the events to trim the budget without compromising security, but balked at the suggestion to use the army instead of the police to maintain security and perhaps save between $100 million and $200 million.

Toews said he was uncomfortable using the army in a civilian context unless under extreme conditions, and went so far as to blame the decision to not consider the measure on what he believed would be a negative reaction from the opposition.

"You know of course what the opposition parties would say. The Liberals would say, ‘The army, in the streets, with guns?'" Toews said.

"It's exactly the kind of fear that Liberals want to invoke in terms of Canadians. Canadians understand that in a democracy, you have the police rather than the army in the streets. And so those are political decisions you make, but I think they're from a perception point of view very, very important."