The bus driver, employed by a Kaitaia company, was badly shaken, Ewers said, but neither he nor anyone else had been injured.
The bus company sent another vehicle to Te Paki to collect the passengers.
The police Serious Crash and Commercial Vehicle Inspection units were both investigating, while WorkSafe NZ was also likely to conduct an inquiry. The bus had been impounded for an examination.
The man's body had been taken to Kaitaia, and the death had been referred to the coroner, who would decide whether a post-mortem examination would be required.