Two people have been injured in a ute and truck and trailer crash north of Auckland.
The crash happened near Schedewys Hill south of Pohuehue about 11.15am and is blocking State Highway One.
The New Zealand Transport Agency said the highway was closed while the truck is removed.
Authorities are warning the crash was causing significant congestion and was expected to for some time.
A heavy haulage truck was needed to move the truck and trailer unit and those travelling through the region were being told to avoid the area if possible.
The NZTA asked motorists to delay travelling through the area to avoid the traffic chaos.
St John Ambulance said one person is in a serious condition and another had minor injuries. Both were taken to North Shore Hospital.