OTTAWA - Canada's big city mayors are urging the federal government to keep billions of dollars in infrastructure money flowing as the country enters a new era of restraint.

They want Ottawa to extend the $4-billion federal infrastructure stimulus fund for at least six months past the current March 2011 deadline -- and consider more funding even as it looks to save money elsewhere.

They're also urging the government to resist the urge to cut other programs -- including the gas tax fund and GST rebates -- that help municipalities build and repair roads, bridges, sewer systems and other infrastructure.

The mayors argue that spending on infrastructure will actually help the government erase the $56-billion deficit racked up since last year's recession, creating jobs, spurring economic growth and generating revenue to fill depleted federal coffers.

"The best way to fight federal deficits is to have people working and paying income and sales taxes," said Toronto Mayor David Miller.

Infrastructure projects to improve things like public transit not only create constructions jobs, he said, they help foster a more positive, productive environment for business, "which in itself creates jobs."

Without continued joint investments in infrastructure by federal, provincial and municipal governments, Miller predicted: "Canada won't succeed, the economy won't succeed."

Regina Mayor Pat Fiacco agreed that infrastructure funding "more than pays for itself" and must not be sacrificed on the altar of restraint.

He's organizing a national summit in Regina early next year involving all three levels of government. The aim is to come up with a 20-year plan for funding infrastructure improvements.

"We have to agree on a plan," Fiacco said. "The federal government is going to look at ways in which they're going to control their spending over the next number of years. That can't be at the expense of reducing the quality of life in Canada for Canadians."

The mayors made their pitch as federal Finance Minister Jim Flaherty is preparing to unveil a budget on March 4. Among other things, the budget will launch a review program to identify spending that can be cut as the government attempts to return to balanced books.

Flaherty has been insistent that the binge of stimulus spending -- launched in last year's budget as part of a temporary, two-year plan to see the country through a deep global recession -- will not continue past March 2011.

However, the mayors said many infrastructure projects can't be finished by the deadline. That's particularly true in smaller municipalities, which took longer to get projects off the ground due to a scarcity of contractors and matching funds.

Fiacco said mayors want the deadline extended to October 2011 or even December of 2011. He said federal officials have not categorically rejected the idea.

"It would be a shame if that deadline would stop some very, very important infrastructure (projects)."