A St John Ambulance spokeswoman said a 55-year-old man had been taken to Tauranga Hospital in a critical condition.
The man's condition was unknown last night.
Three fire engines also attended the crash.
Extensive road diversions were put in place, and the highway only reopened at 3pm.
Two residents, including a man who said he was three paddocks away from the crash site when he heard an "almighty loud bang".
"I was too far away to see the crash, but I saw what was either a lot of dust or smoke rising in the air from around that location," he said.
Another local man said he too heard a huge bang from at least 400m to 500m away.
"It was a hell of a noise, and when I ran up to the road, I could see quite a few vehicles parked up and lots people were running up to see what they could do to help the truck driver and the person in the motorhome.
"It was a bit of a frantic scene at first until police arrived," he said.
The Serious Crash Unit was still investigating the cause of the crash last night.
