In March, the federal government had allocated $179 million for its security budget. But under new estimates, these costs should increase by $654 million to a total of $833 million.

Public Safety Minister Vic Toews told CTV's Power Play Tuesday evening that costs could rise by another $100 million, and so the government has budgeted up to $930 million on a "medium-threat basis."

"When I first looked at it I think the reaction would have been the same as any ordinary Canadian looking at those costs," Toews said. "You say, ‘How much money is this costing us?' But I'm satisfied that the experts have been very careful in their assessment."

"We don't want to have a security incident," Toews added. "Security is the biggest concern that we have in putting these summits on."

Toews said the government won't know the total security costs until after the completion of the summits.

The new costs are included in the Supplementary Estimates (A), 2010-11 -- the first of several documents used to inform Parliament about spending requirements that are not included in the Main Estimates of the annual budget. Continued...