Auckland's Northern Motorway will be fully closed 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 - and is already causing significant delays and disruptions for rush-hour commuters.

The right-hand lanes in both directions are currently closed, with only two lanes open each way - causing "long delays" in both directions, Waka Kotahi NZ Transport Agency warned motorists.

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 lane closures are causing significant delays for Auckland commuters as of 6pm. Photo / Supplied

Commute times are already mounting for Auckland drivers.

A trip from Auckland CBD to the Westfield Albany mall, which would usually take around 19 minutes, is taking 90 minutes via SH1 as of 6pm, according to information on the NZTA website.

The fastest route from the central city to Albany is SH16, where the commute is 56 minutes instead of the usual 29 minutes.

"Avoid this route if possible or allow considerable extra time."

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 tomorrow.

The repair will involve stripping the road surface, removing the grout material and then paving with asphalt, NZTA said.