But Infrastructure Minister Alan Tudge says less than half of the existing 166 projects under the $4 billion fund are set to go to construction in 2020.

"Nine of those projects are already either in construction or out to tender as we speak, 69 of them will be in construction phase this year," Mr Tudge told reporters in Canberra on Wednesday.

Deputy Prime Minister Michael McCormack said they had written to the states calling for projects.

"If there's a program that we can roll in the next three to six months ... then we will do so," Mr McCormack said.

Labor's infrastructure spokeswoman Catherine King said the new call to the states was a clear admission the Morrison government's previous infrastructure package was a marketing ploy.

"Now with the economy in a weaker position, (Prime Minister) Scott Morrison's infrastructure minister's great idea is to beg the states for help," Ms King said.

"It's well past time for the Morrison government to deliver a real plan for infrastructure."

The funding was aimed at roads projects to foster local jobs after recommendations by the Reserve Bank of Australia, with states chipping in to the costs.

When questioned on the delays, Mr McCormack said the government was undertaking the projects in a "phased" process.

He pinned delays and the new call for projects on the bushfire crisis and coronavirus.

"Back in November last year, some of those challenges weren't presenting themselves, weren't manifesting themselves as they are now," he said.

He said the government would aim to get some of the projects going in three to six months.

Australian Associated Press