The West Gate Tunnel toll road deal cut by the Andrews government will help Transurban not trigger a "super-profits" clause in its CityLink contract ending tolling a decade early, a report by Macquarie Bank has confirmed.

Melbourne motorists could have stopped paying tolls as early as June 2026, within eight years, if equity return topped 17.5 per cent over the life of the CityLink contract, according to a briefing note to Treasurer Tim Pallas this year.

Transurban is projected to take tolls of more than $1 billion a year across CityLink and the West Gate Tunnel by 2026, Credit:Jessica Shapiro

But signing up for the West Gate Tunnel, a new toll road under Yarraville pitched by Transurban to Labor, removes any possibility of the trigger to wind up the toll contract earlier than 2035.

If the plan gets through Parliament – the Coalition and the Greens have both vowed to stop it – motorists will pay tolls on CityLink and the new West Gate Tunnel until 2045.