The federal government is coming under increasing scrutiny over the amount of money it has budgeted for infrastructure spending, as local and provincial governments get ready to apply for funding under a new federal plan.

In a surprise move on Friday, the government declared the 10-year, $14-billion New Building Canada Fund open or applications three days ahead of schedule. It was originally set to launch on March 31.

"Today's official launch of the New Building Canada Fund, means that the entire New Building Canada Plan is now 'open for business,' ensuring a seamless transition to the new program," Infrastructure Minister Denis Lebel said in a news release Friday.

The New Building Canada Fund includes $4 billion for projects of national importance, $9 billion for provincial and territorial infrastructure projects, and $1 billion dedicated exclusively for projects in small communities with under 100,000 residents.​

The New Building Canada Fund is part of a larger 10-year, $53 billion New Building Canada Plan. 

But Canada's mayors and federal opposition critics say $14 billion simply isn't enough to improve Canada's roads, water systems, or public transit.

During a news conference in Ottawa on Thursday, Liberal infrastructure critic MP David McGuinty accused the Conservatives of delaying the majority of that spending until after the next federal election in 2015.

"It's a 10-year plan, which we were happy to see, but it's heavily back-end loaded and extremely light on funding until after the next election," said McGuinty.

The government's 2013 budget shows the Conservatives will invest $210 million in the new Building Canada Fund in 2014-15, and another $210 million in 2015-16. Investment in the new fund will start increasing in 2016-17, after the next federal election.

McGuinty said the new fund doesn't get back to providing the same level of funding as the old program did until the year 2019-20, when the government will invest $2 billion.

The Liberal MP also accused the Conservatives of eliminating the deficit at the expense of infrastructure spending, pointing to a report by the budget watchdog showing that approximately $10 billion each year, for the last three years, has gone unspent by the government.

Lebel's office issued a written statement in advance of McGuinty's news conference, saying the Conservatives have "no lessons to learn from the Liberal Party regarding infrastructure funding."

"Unlike the Liberals, when they were in government and spent peanuts on infrastructure, we are delivering long-term, predictable funding for Canada’s infrastructure," the statement said.

'Open for business'

Lebel appeared before the Commons committee on transport, infrastructure and communities on Tuesday, for the first time since unveiling the new infrastructure fund last month.

The minister said that municipalities would have $2 billion from the Gas Tax Fund available to them beginning April 1, and that $6 billion in funding from the old infrastructure fund would continue to flow across the country this year and beyond. 

Lebel's testimony did little to quell the concerns of mayors across the country who have been asking for a "guaranteed" share of the funds.

NDP infrastructure critic Marjolaine Boutin-Sweet asked Lebel during his appearance at the committee how much of the $14-billion fund would be dedicated to municipal projects.

The minister made it clear Tuesday that it is up to the provinces – not the federal government – to decide how much money will go to improve Canada's roads, water systems, and public transit.

'With less than a week left, local governments remain concerned about their ability to deliver the critical fixes to infrastructure that their communities need.'- Claude Dauphin, president of the Federation of Canadian Municipalities

"It's impossible for me to tell you today how much money will go to municipalities," Lebel said.

"They will have to apply through the provincial-territorial program, after that the provinces will decide which are their priorities, and after that in some years from now we will be able to say this amount of money has been invested through municipalities."

Following Lebel's testimony, the Federation of Canadian Municipalities, a group that represents more than 2,000 communities across the country, said their concerns remained unanswered.

"With less than a week left, local governments remain concerned about their ability to deliver the critical fixes to infrastructure that their communities need," said Claude Dauphin, president of the FCM, in a written statement to CBC News on Tuesday.

"For municipalities to actually begin construction on projects, the government needs to have programs officially up and running, and those programs need to be designed right if they're going to deliver the best value for Canadians," said Dauphin.

A spokesperson for Lebel told CBC News on Wednesday that the New Building Canada Plan would be "open for business on March 31."

"Details on how interested parties can apply for funding will be made public on Infrastructure Canada's website Monday," Michele-Jamali​ Paquette, the director of communications for Lebel said in an email to CBC News.​