More Sydney motorists are likely to use the first tunnel to be opened as part of WestConnex than government modelling originally forecast, new data suggests.

Consisting mostly of tunnels, the M4 East from Homebush to Haberfield is due to open to motorists by June. Motorists have been paying tolls since August 2017 on a widened section of the M4 between Parramatta and Homebush, which forms part of the first stage.

Analysis by Macquarie Group of new data on vehicles using Sydney's toll roads shows traffic exiting and entering the widened M4 in November averaged almost 67,000 vehicles a day.

The M4 East tunnel is due to open to motorists within the next four months. Credit:Steven Siewert

Given the government's baseline forecast for traffic on the new M4 East, which will link to the widened section of motorway, is about 68,000 vehicles a day, the Macquarie analysts said the data suggested that the state's expectations would be surpassed.