State Highway 6 through Kawarau Gorge will close overnight from Sunday to Thursday for eight weeks from August 31 while work is carried out to repair an underslip.

The closures, just north of the Goldfields Mining Centre, will run from 9pm to 6am the following morning, with the road reopening on the hour to allow queued traffic through. There will be no closures during the day, or between 6am Friday and 9pm Sunday.

NZ Transport Agency Waka Kotahi said delays of up to an hour could be expected during the overnight closures.

During these nightly periods of closure, the highway will open every hour, on the hour, and any waiting traffic will be piloted through a single lane at the site, Waka Kotahi said in a statement.

Oversize vehicles will be accommodated if operators follow permit requirements and give prior notification.

The work, being carried out by Aspiring Highways on behalf of Waka Kotahi, will strengthen the retaining wall at Scrubby Corner. This involves boring anchors into the rock behind the wall and structurally connecting them to reinforce the crib wall.

The project is scheduled to finish by October 23. Motorists can check current conditions on the road in The Central App.

PHOTO: Waka Kotahi