In a tricky issue for opposition transport spokesman Anthony Albanese, who faces a tight contest for the inner-city seat of Grayndler, Labor has said the $3.5 billion federal funding for the project is already in the hands of the state government.

Mr Albanese has also said that he would not commit any further funds to the 33-kilometre motorway.

But both the state and federal governments intervened this week to say that about $2.3 billion in funding – in the form of a $300 million grant and a $2 billion concessional loan – is not due to be transferred until after the July 2 election.

The Greens, Mr Albanese's opponents in Grayndler, oppose all funding for Australia's largest toll-road project and say future federal money should be frozen.

In the 2015 state election, Labor's equivocation on WestConnex contributed to its failure to win two seats in the inner west: Newtown and Balmain.

On Tuesday, Labor leader Bill Shorten repeated Labor's previous claim that the $3.5 billion had already been paid.

"The truth of the matter [is] the government has paid the money and they are trying to work out where the project goes," he said.

Mr Albanese told a community forum two weeks ago that Labor would not commit further funds to the project. He has criticised the project's business case, and that it did not connect directly to the port or the central business district.

Mr Shorten said on Tuesday: "We do support WestConnex. But we have said, Anthony and I, the WestConnex project isn't satisfactory in that it doesn't go to the ports and the city."

But according to the Liberal NSW and federal governments, $300 million in grant funding "will be a matter for the incoming federal government".

And all but $38 million of a $2 billion concessional loan will be drawn down by WestConnex in the four years after the election.

Major Projects Minister Paul Fletcher accused Mr Albanese of "walking two sides" in telling a community meeting two weeks ago that a Shorten government would not spend one extra dollar on WestConnex, but later saying the funding committed so far would be honoured.

"If it's Mr Albanese's hand that has to sign the paper for that money to flow, you'd have to be very worried about whether that existing federal commitment for WestConnex is still there," he said.

The wedging of Labor over the project comes two weeks after the National Audit Office revealed it will scrutinise the federal government's decision to commit the direct funding and concessional loan to WestConnex.

To be built in three stages, the motorway project relies on funding from the federal and state governments, as well as on tolls from motorists.