Motorists are being urged to plan ahead with a major overnight road closure set to affect one of Perth’s busiest commuter routes.

Stephenson Avenue will be closed in both directions over the Mitchell Freeway from 9pm on Wednesday until 5am on Thursday as crews carry out asphalting works on the major road upgrade.

Main Roads WA says drivers in the Stirling and Innaloo areas will need to follow detours via Hutton Street and Karrinyup Road, with delays expected while the work is underway.

The closure forms part of the Stephenson Avenue Extension project, which is creating a new east-west link across the Mitchell Freeway and improving access to Stirling Station and the surrounding road network.

Motorists travelling through the area overnight are being urged to allow extra travel time, follow the signed detours and drive with caution through the work zone.

The road is scheduled to reopen by 5am on Thursday, in time for the morning peak.