A plan to build 75 new trains for Melbourne, 75 new E-class trams and 24 new V/Locity rail cars for V/Line will be promised at the Napthine Government's campaign launch in Ballarat on Sunday.

Transport Minister Terry Mulder said the 75 newly pledged suburban trains will come into service between 2019 and 2026.

But Labor labelled the promises "a con" and pointed to broken promises on public transport made by the Coalition at 2010 election - including a pledge to put 10 new trams on the tracks. None of these trams were delivered.

"And they specifically promised they were not going to build the East West Link last time. But they did promise a Doncaster rail line, Avalon rail and 40 new trains," Opposition scrutiny of government spokesman Martin Pakula said.

"How can any of their commitments be believed this time?"