Main Roads is reminding Perth motorists the Northbridge Tunnel eastbound will be closed this weekend.
The eastbound lanes will be blocked off from 10pm tomorrow night until 5am Monday, April 15.
Motorists are advised to use alternative routes.
The closure, originally scheduled for 9pm tomorrow night, has been pushed back an hour because of Friday night football at Patersons Stadium.
The works are part of a project to add an extra lane to the tunnel in both directions.
This weekend is the last scheduled closure for the eastbound lanes, with three separate closures remaining for the westbound lanes, specifically April 19-22, April 22-23 and April 26-29.
The new lanes are expected to open next month.