Tram drivers have deliberately timed a strike to coincide with the Australian Open, to have maximum impact in an escalating pay war.

About 1500 drivers and customer service workers at Yarra Trams will down tools for four hours between 10am and 2pm on January 28 and 30.

At the same time, thousands of people will be heading to the Australian Open semi and quarter finals.

Yarra Trams slammed the "unnecessary disruption" to the public, while the Rail Tram and Bus Union claimed to have been forced into action.