In a statement released on Monday night, it said it had lodged an application to the Fair Work Commission to terminate the strike.

"As this week's planned industrial action poses a safety risk to the travelling public and our employees, today we lodged an application in the Fair Work Commission to terminate the industrial action," the statement said.

The Fair Work umpire last week rejected Yarra Trams' same argument that industrial action levelled against it posed a safety risk.

Metro has offered staff a pay rise of 14 per cent over four years, but the union says the entire enterprise agreement being offered by the rail operator is "not in its members' interests".

The union has approval from Fair Work for its members to also carry out industrial action such as temporary shutdowns.

The union gave the required five working days' notice of the strike on Thursday.

Metro issued a statement, declaring there had been no "meaningful" progress with the Rail, Tram and Bus Union and that no negotiations were held on Monday.

"We are doing all that we can to continue to deliver efficient and safe train services for our customers," the statement said.

"We are at an impasse so have escalated this to the industrial umpire.

"We remain committed to delivering the services our customers rely on."

The union shut down Melbourne's tram system for the first time in 18 years on Thursday, hampering tens of thousands of commuters and leaving many stranded on a rainy Melbourne day.

The train strike is planned for between 10am and 2pm on Friday.

With Clay Lucas and Adam Carey