The growing lag between Labor's return to government in November and the expected order of trains has put Victoria's rail manufacturers in an increasingly tenuous position, with some contemplating job losses this year.

Ballarat manufacturer Alstom already faces at least four months' enforced downtime once its current contract assembling eight X'Trapolis trains for Metro ends in July.

Union and rail company representatives held urgent talks last week with government MPs to stress the need to fast-track new rolling stock orders.

"Last time around when things went quiet at Alstom, they had our members doing the gardening and sweeping the floors until work picked up," Australian Manufacturing Workers Union assistant state secretary Craig Kelly said. "But Alstom has indicated they aren't going to do that again."

Up to 600 Victorians are employed in rail-related industries across five sites statewide, but Mr Kelly said work was quickly drying up and staff were growing anxious.

"The workers are very nervous for their future," he said. "This is their work, their lives, and with the major car builders finishing up in 2016, they don't see too many other jobs on the horizon."

Alstom spokesman Sheldon Young said the company had made no call on its future beyond July.

"We are still dedicated and focused on delivering the current batch [of eight trains] and we're ahead of schedule again," Mr Young said.

"In the interim, we're trying to do what we can to secure a pipeline in the future."

Labor leader Daniel Andrews visited Alstom's Ballarat plant in October to announce a promise to order 30 new suburban trains and 20 V/Line rail cars, with contracts to be awarded to whichever bid employed the most Victorians. Companies were advised at the time to "start preparing their bids", but are still waiting for further word four months later.

Wendouree Labor MP Sharon Knight said there were real concerns about looming job losses in Ballarat but that she was "committed to fighting for Alstom's future".

"Unfortunately, the budget doesn't come down until May, and our commitment was for rolling stock in the first budget. But I am talking to everyone I can about what we can do in the meantime."

Work is also drying up among smaller businesses that supply components to Alstom.

Committee for Dandenong board member Jill Walsh warned that if Alstom's Ballarat plant closed, smaller suppliers would die with it and Victoria could permanently lose its rail manufacturing skills.

"If the rail work doesn't come through there is a whole skill set that will disappear. You will never have them set up here again," Ms Walsh said.

Ms Walsh is a partner in Actco Pickering, which supplies train components to Alstom. That work will end in late May or early June, she said.

Tim Piper, Victorian director of the Australian Industry Group, advised nervous employers to sit tight until the May budget.

"We don't want to force the government's hand and not get a decision that is best for the long-term," Mr Piper said.

Public Transport Minister Jacinta Allan blamed the uncertainty on the former government, who she said "failed to extend their rolling stock order and commit to an ongoing supply of work".

"As we announced last Friday, our rolling stock strategy will be part of this year's budget but we are aware of the urgency around securing a pipeline of work for Alstom," Ms Allan said.

Shadow Public Transport Minister David Hodgett said Alstom's staff needed certainty, not excuses.

"It's not fair on these families to have the stress of unemployment because of Daniel Andrews' lack of action," he said.