Stephen Harper hit back Friday at criticisms by Liberal Leader Michael Ignatieff over the unspecified details of the Conservatives' $3 billion emergency stimulus fund, which the prime minister says needs parliamentary approval "immediately."

The fund is designed to get cash flowing to projects far sooner than June, when the budget's supplementary estimates would normally be adopted by Parliament.

During question period in the Commons on Tuesday, Ignatieff asked for more details on how that money would be spent.

"We cannot write a blank cheque on $3 billion worth of stimulus," said Ignatieff. "We have to have some indication of what this is going to be spent on."

Harper, speaking Friday in Berwick, N.S., where he joined Premier Rodney MacDonald in pledging $17.5 million to widen part of Highway 101 through the province's Annapolis Valley, said his government needed "flexibility" in order to put the money to use as quickly as possible.

Details on spending coming in June

Harper avoided specifics with regard to what the fund would be used for, pointing to Friday's announcement as an example of how his Conservatives are "speeding up funding through building Canada."

"We still need that parliamentary authority to bring the new programs in to place quickly, and we can't do that unless we get some authorization immediately."

He said details of the how exactly the money would be spent will come between now and June.

Ignatieff said Tuesday more detail on specific spending plans for the $3 billion emergency stimulus fund is a reasonable demand during the process. But Harper argued the Liberals were not being realistic.

"There is no excuse for an opposition that has been saying 'we need to deliver money more quickly' to now say 'we need to delay that money' or say things like 'we need to have parliamentary sign-off on every individual project,'" Harper said.

"Rather than trying to throw up roadblocks, they need to get out of the way and let that money flow," he said.

Goodale tries to play down friction

Liberal House Leader Ralph Goodale said Friday his party is not seeking a confrontation with the Conservatives over the fund. Harper had previously said that the fund is a matter of confidence, and a vote against it by opposition parties would force an election.

The Liberals plan to table a motion Monday calling on the government to detail how the money is to be spent.

But Goodale said they won't debate the motion or force a vote on it until late March, giving Liberals and Conservatives several more weeks to reach a compromise.

With files from the Canadian Press