Victorian Labor could build a giant L-shaped pier south-west of Melbourne to become the city’s second port.

A huge L-shaped pier could be built southwest of Melbourne to become the city’s second port, Labor says.

The kilometres-long pier would have to be built well offshore to let large container ships unload, as that part of Port Phillip Bay is too shallow.

Labor’s Bay West proposal, near Werribee, would be a second port to the Port of Melbourne, which is due to exceed its capacity in the next 15 years.

But the coalition government said Labor “still doesn’t get it” on ports, as the Bay West plan would mean substantial dredging of the bay.

The state government favours a second port at Hastings, south-east of Melbourne.

The Labor plan would have large ships dock at the pier to unload containers, which would then be loaded onto trains via an “island terminal”.

Labor has left itself some wriggle room, promising to submit a proposal in favour of Bay West after the election, rather than promising to build it.

Shadow Treasurer Tim Pallas said Labor would establish Infrastructure Victoria to independently plan the state’s large priority projects, including Bay West.

“Labor will determine the viability of Bay West as the location for Victoria’s future container port as we believe it could be a nationally significant investment for the Geelong region,” Mr Pallas told AAP on Wednesday.

Victorian Major Projects Minister David Hodgett said the Labor plan hadn’t been thought through.

“They still won’t be able to get the big ships through the (Port Phillip Bay) Heads without massive dredging, without deepening, without blasting the Heads,” Mr Hodgett told reporters.

“I’d hate to be Labor’s environmental minister to make the decision of which national park they want to blow up to widen the Heads.”

Mr Pallas has previously denied the Heads would need blasting to get big ships in.

He also said the Bay West proposal had more going for it than the Hastings plan.

“Bay West has a number of advantages over Hastings, including availability of land, access to major arterial roads, standard gauge national freight network (and) potentially unlimited berth capacity,” Mr Pallas said.

Labor said Bay West had the potential to take 10 million TEU (twenty-foot equivalent unit) ships, compared with nine million TEU at Hastings.