A woman is in a serious condition in Waikato Hospital's high dependency unit after being involved in a vehicle accident in the Karangahake Gorge shortly before 4pm on Monday.

Paeroa police say a crash between two cars and a light truck closed both lanes at the Paeroa end, with it remaining fully closed until about 7pm.

The woman was retrieved from the accident scene and flown to Waikato Hospital by an Auckland based rescue helicopter.