Work is underway to widen the West Gate Freeway and build the citybound entrance for the West Gate Tunnel.

Four extra lanes will be created on the freeway between Williamstown Road and the M80 Ring Road, bringing the total to 12.

Drivers will notice changes on the West Gate Freeway as workers establish a construction site, install traffic barriers and change line markings.

This work is to prepare for moving the inbound exit ramp at Williamstown Road further north, to make space for the West Gate Tunnel citybound tunnel entrance.

All lanes will be open during peak travel periods while the works take place.