A part of Auckland's Northern Motorway will close from 9pm this evening for urgent repairs to damage caused by roading contractors.
The closure to State Highway 1 between Greville Rd and Upper Harbour on the North Shore is due to roading construction work gone wrong.
The right-hand lanes in both directions have been closed since early evening, which caused long delays for commuters trying to get home at rush hour.
Congestion in the area is now easing.
At one point this evening, commute times for some motorists more than doubled.
A trip from Auckland CBD to the Westfield Albany mall, which would usually take around 19 minutes, took around 90 minutes via SH1 at 6pm, according to information on the NZTA website.
From 9pm, all lanes in both directions will be closed from SH1 Upper Harbour Highway to the Greville Rd Interchange.
Motorists are urged to avoid the motorway by using local and alternative roads or to follow detour signs in the area, NZTA said.
The road surface across the two lanes has lifted, causing a significant speed bump for vehicles, the agency said.
An investigation has found the uneven surface was caused by road construction crews working under the raised motorway section.
"They were pumping grouting material which became blocked and seeped out under the road surface, causing it to lift."
Crews will work through the night to repair the road, which is expected to be open by 5am on Wednesday.
The repair will involve stripping the road surface, removing the grout material and then paving with asphalt, NZTA said.
Meanwhile, a crash further south at around 6.30pm also caused delays for Auckland commuters this evening.
The collision on the Southwestern Motorway (SH20) blocked the right-lane northbound near the Hillsborough Rd on-ramp.
NZTA warned drivers in the area to expect delays.