Seven people have been injured, one seriously, following a two vehicle crash near Taupiri.
Emergency services were called to State Highway 1 just before midday.
The highway is closed at Great South Road and traffic is being diverted south through Ngāruawāhia.
A helicopter has been sent to the scene.
State Highway 3 in Whanganui is also closed, after a car hit a power pole on Huxley Road.
Police were called to the serious crash just after 11am.
Motorists are being advised to avoid the area.