Two weeks from the state election, the Barnett Government has yet to submit its full business case or receive any of the promised Commonwealth funding for its priority road project, the $1.9-billion Perth Freight Link.

Infrastructure Australia still lists the project as one of the nation's high-priority infrastructure projects, alongside others such as a second airport for Sydney.

But senior executives from the Commonwealth Department of Infrastructure have told a Senate Estimates hearing in Canberra the full proposal for the project's second stage, known as Roe 9, has not yet been received, assessed or approved.

The Commonwealth has pledged, but so far not provided, $1.2 billion for the Perth Freight Link project, with the balance of $700 million committed by the Barnett Government.

Intended to provide a seamless heavy transport link to Fremantle Port, critics have attacked the project as a road to nowhere that will shift, rather than relieve, heavy transport congestion.

Much of the criticism has centred on the planning for the project.

The State Government initially committed to building the Roe 8 extension of Roe Highway across the Beeliar Wetlands to Stock Road, without finalising its plans for Roe 9 to Fremantle.

Since then, it has been engaged in a battle of attrition waged by environmentalists and other opponents trying to slow progress with Roe 8 in the hope of a change of government on March 11.

No funding until proposal submitted

The project has been dismissed by WA Labor, which has promised to immediately axe Roe 8 and Roe 9, scrapping the Perth Freight Link if it wins office two weeks from now and instead building its flagship Metronet rail project.

But when he arrived in WA for a one-day visit last week, Prime Minister Malcolm Turnbull warned Labor the money had been pledged for Perth Freight Link, and could not be transferred to another project.

He told ABC Radio Perth the freight link, unlike Labor's Metronet proposal, was ready to go.

"You can't compare the two. The freight link project has been designed. The project has been around for a long time. It's been carefully assessed by Infrastructure Australia. It's a priority project," he said.

But under questioning from WA Greens senator Scott Ludlum, Infrastructure Australia confirmed the agency was yet to grant final approval for funding for Roe 9 because it had not yet received a project proposal report, or PPR, from the Barnett Government.

"We are yet to receive any such documentation and no funding has been provided to date," Department of Infrastructure secretary Mike Mrdak told the hearing.

Until that report is provided, reviewed and approved, WA will not receive a cent of the promised Commonwealth funding.