Melbourne motorists face decades of tolls

Melbourne motorists will keep paying tolls until 2045 to cover the $3.5 billion needed for a new toll road.

Victoria has committed $2 billion to the $5.5 billion Western Distributor, which will connect freeways in the city's west and north.

The remaining money will come from toll road operator Transurban, whose monopoly on the Melbourne's toll roads will be extended from 2035 to 2045.

Transurban chief executive Scott Charlton said the project would deliver $11 billion in productivity improvements for the state.

"We think it's good value for the state of Victoria and it's good value for our shareholders," Mr Charlton told reporters on Thursday.

Premier Daniel Andrews said Victoria stepped in to help fund the project after Canberra refused to chip in.

"Malcolm Turnbull made it very clear he's not interested in being a partner in this project. Well, this project simply cannot wait," Mr Andrews told reporters.

Residents will be able to have their say on the latest design options in a community consultation starting on April 16.