Dairy products are spilling into the Awakino Gorge on State Highway 3 after a serious milk tanker crash this morning.
Emergency services were called to the crash, just south of the tunnel in the Awakino Gorge about 5.30am.
The driver was trapped for about an hour before being flown to Taranaki Hospital with serious chest injuries, Radio New Zealand reported.
The truck was carrying evaporated whey permeate, a dairy by-product used in making cheese. Milk and other similar dairy products are toxic to fish and aquatic life.
Waikato Regional Council emergency response manager Rob Dragten said the tanker has lost almost all of the 25,000 litres of the dairy product.