Metlink chief executive officer Bernie Carolan, has applauded the federal government's decision to invest $3.2 billion in the Regional Rail Link that will boost the long-term capacity of Victoria's train network and provide much-needed relief for public transport commuters.

The Regional Rail Link will be a 40 km rail-line spanning from Werribee to Sunshine and will be used by Geelong, Ballarat and Bendigo trains to run directly into Melbourne. The extra capacity provided will also allow for more services on the Werribee, Sunbury and Craigieburn lines.

"The link will greatly assist in servicing the rapidly expanding suburbs to the west and north-west of Melbourne plus provide additional capacity for services travelling through the congested central area," Carolan said.

"Our research tells us that 92 per cent of Melburnians want governments to spend more on public transport infrastructure, ahead of offering tax cuts, reducing the price of petrol and building new roads."