State Highway 1 at Otaki is now open in both directions after a truck and trailer unit crashed into a power pole earlier.
NZTA has advised the traffic signals are still out and significant delays remain.
Most power has been restored to the area after about a thousand Electra customers were left without.
The truck and trailer unit had earlier crashed into a power pole in Otaki, closing State Highway 1 in both directions.
The incident happened just before 5pm at the Mill Road roundabout.
A police spokeswoman said no one was injured in the incident but power lines had fallen onto the road.
An Electra outage map showed almost 1000 people were without power in the area.