A Fire and Emergency New Zealand spokesman said two trucks were at the scene about 5.40pm.
Police said the road would be closed for at least three to four hours and advised motorists to avoid the area if possible.
Waka Kotahi NZ Transport Agency said at 6.50pm that the highway was closed between Hot Springs Rd and Sharp Rd in Aongatete.
"Our crews are on-site, and cordons are being set up. There are heavy delays around the crash scene, so please avoid the area if possible.
"At this stage, the road is likely to stay closed for a few hours, firstly for a serious crash investigation to take place, then followed by crash clean-up."
Emergency services were also called to an earlier crash on Omanawa Rd.
A Hato Hone St John spokesman said it was notified of the incident at 2.04pm and had sent one ambulance and a rapid response vehicle.
One person was transported by road to Tauranga Hospital in a moderate condition.
Police said it was a crash involving a single vehicle that left the road.