He said the truck was carrying four empty portaloos.
"There have been no spills or environmental impact from the vehicle or the portaloos."
He said it looked like the truck had accidentally slipped off the road at low speed.
The truck will likely be written off. The value of the truck and portaloos was about $120,000, he said.
It was the second truck crash in rural areas around Napier in less than an hour.
Two trucks had collided at about 4.20pm on Awatoto Rd, alongside the fairways of the Awatoto public golf course. Police said one person was taken to hospital with minor injuries, but the section of road was closed to traffic for about three hours.