A project that would replace 3500 container trucks a day with just 28 freight trains, potentially halving port-based truck traffic and slashing pollution levels from heavy vehicles, has been shelved by the Andrews government until it leases Melbourne's port.

The port-rail shuttle project has been suspended despite having $58 million of state and federal money committed to it last year, dismaying businesses eager to see the huge transfer of container freight from trucks to trains.

Commercial property developer Salta is poised to invest $3 million on a one-kilometre rail spur to link its Altona freight terminal to the port, plus $30 million on freight facilities on its site, but said it was pointless spending the money while the port-rail shuttle is on ice.

"Salta has an obligation to build that [rail spur] once certain things have happened, but there is no point until trains can be received at the port," the company's managing director Sam Tarascio said.