The wreckage from a truck crash is still affecting State Highway One north of Welllington more than 12 hours after an accident this morning.
Northbound Ngauranga Gorge is reduced to two lanes.
At 9pm two southbound lanes will be closed and traffic will be diverted down a slip lane and back down to Newlands On Ramp.
There will be a full southbound closure between Newlands and Churton Park for approximately 20 minutes overnight to allow the truck to be towed away.
All lanes are expected to re-open by 5.30am tomorrow.
The New Zealand Transport Authority said the truck had damaged the median barrier and surrounding poles which had made it difficult to remove.