Metro Trains has pleaded with the public transport union to fast-track negotiations over the latest wage deal to avert a possible 48-hour strike on the city's network.

Yarra Trams' drivers and customer service staff have joined rail workers in a bitter fight for a 6 per cent pay rise, with 1500 members of the Rail, Tram and Bus Union voting to take industrial action that could include strikes of up to 48 hours.

Metro chief executive Raymond O'Flaherty on Thursday afternoon. Credit:Jason South

It comes days after the union announced it would launch rolling industrial action on the train network starting on Monday, as thousands of drivers and station staff will refuse to check myki tickets, keep ticket barriers shut, wear uniforms and do overtime.

The ban on checking tickets on trains is scheduled for Monday, August 12, and the following Monday, August 19.