State Highway 2 at Maramaru re-opened at 7am this morning after being closed since 4.00am by an accident.

A land cruiser crashed off the highway and rolled hitting powerlines. A woman was flung from the vehicle, and has since been flown by rescue helicopter to Middlemore Hospital in a serious condition, Stuff reports.

She was one of five people in the vehicle. Four other people in the vehicle were also injured and have been taken to hospital, says Senior Sergeant Ray Malcolmson of Waikato police.

Two were flown and two were taken by road ambulance, he said. They suffered moderate injuries.

Northern Fire Communications shift manager Jaron Phillips said the truck was completely blocking the highway and had brought down powerlines across the road. Brigades from Maramarua, Mangatangi and Mercer attended the smash.