Fears have been raised that partial closure could lead to a complete shutdown of the Williamstown line, raising the spectre of similar plans touted during the Kennett era.

Victoria's new train operator, Metro, last week announced the Williamstown and Alamein lines would be the first to have services cut if trains were needed on busier lines.

Buses last week replaced trains between Newport and Williamstown as temperatures topped 40degrees.

There are three stops after Newport until the end of the Williamstown line, including Williamstown Beach station.

Some commuters fear they could be forced to travel to Newport on the Werribee line train via North Melbourne.

Changes to the Williamstown line would also affect Seddon and Yarraville commuters, particularly if the Werribee train was running express and bypassing their suburb.

In the early 1990s, a community campaign successfully fought to keep the Williamstown train line after the former Kennett government argued low patronage did not justify operating costs.

Veteran campaigners and Williamstown residents last week demanded the State Government clarify its public transport policy.

Suzanne Orange was angry that Williamstown had been identified as a line that could be shut down to prop up other Melbourne services.

"Could the Premier and minister for transport confirm if this is the new transport policy for Williamstown?

"Jeff Kennett tried to shut our train service down. Is John Brumby doing the same?" Ms Orange said replacing trains with buses in such circumstances could also be a breach of the Government's and Metro's obligations to the disabled.

Pamela Pittard said people should be jumping up and down.

"We are being dismissed again and we feel like we're the scapegoats. Why should we have to be sacrificed for other lines. We're entitled to a train service like any other line.

"We may not be as busy as Frankston and we may not be as busy as Craigieburn, but then we haven't got the population and we still pay for our tickets.

"We are being treated as second-class travellers."

Liz McKeag said she was on a tram that crashed in Swanston Street last week, and she was forced to transfer from train to bus at Newport.

"The whole transport system's just so terrible.

"Why are we compromised all the time over in the west?"