Vic train staff to strike next week

Melbourne train staff will strike next week despite Metro Trains promising to dock workers' pay if they take part.

Rail, Tram and Bus Union (RTBU) members at Metro Trains will follow their tram-driving colleagues, and strike on September 4 from 10am to 2pm.

The original plan was for a ban on wearing uniforms and a ban on scanning myki cards, with two stoppages planned before 6am.

But now the union wants to hit Metro Trains harder.

"We do not want to inconvenience the travelling public, but they've left us with no choice," RTBU secretary Luba Grigorovitch said on Thursday.

Ms Grigorovitch said Metro management had threatened to dock union members' pay and stand workers down.

"Our members came in this morning absolutely furious," she said.

But a spokeswoman for Metro said they are required by law to deduct pay when an employee does not perform their role due to industrial action.

"This is not a threat, this is a matter of complying with the law," she told AAP.

"We maintain the view that any industrial action is unnecessary, and we'll do all that we can to avoid any disruption for our customers."

The planned industrial action does not include drivers, who are planning to strike between 2am and 6am the following day.

But after a four-hour tram strike caused chaos across Melbourne on Thursday, industrial action by train staff is likely to cause major problems across the city and its outskirts.

"It will shut the network down," Ms Grigorovitch says.

Workers are willing to return to the bargaining table and put an end to six months of negotiations with Metro, she says.