Debris had spilled onto the road, which was blocked, the spokesperson said.
A Fire and Emergency spokesperson said a fire engine and two rescue trucks were dispatched but the rescue trucks were stood down.
“The crew have arrived at the scene,” the spokesperson said.
“Police and ambulance are in attendance and we are assisting.”
Hato Hone St John confirmed it was notified of a crash on Ohaupo Rd, Ohaupo, at 1.52pm.
A spokesperson said St John responded with one ambulance and one rapid response vehicle.
Crews assessed and treated one patient at the scene.
Police confirmed SH3 between Airport Rd and Kapiaki Rd remained closed at 5.11pm, however it had reopened by 7pm.
A New Zealand Transport Agency Waka Kotahi alert at 3.35pm, SH3 between Airport Rd and Kapiaki Rd said the road remained closed.
“[The road] is likely to remain closed for some time as police conduct a serious crash investigation,” the alert said.
“Allow extra time for short detour via Mystery Creek Rd.”
A Waikato Herald reporter at the scene said traffic was backed up Airport Rd and Mystery Creek as traffic was diverted around the site of the crash.
Maryana Garcia is a Hamilton-based multimedia reporter covering breaking news in Waikato. She previously wrote for the Rotorua Daily Post and Bay of Plenty Times.