Rescuers had not found the driver, who he confirmed is male, and were looking for him, Wilson said.
A police spokesperson said earlier this evening the Mine Incident Controller was leading the rescue effort of the underground mine rescue team and police were co-ordinating at the scene. All mining activities in the area had been halted.
Wilson said earlier mine management were alerted when a manager called the company and said they couldn't reach a worker by radio.
Northern Ambulance Communications' team leader Ngaire Jones said an ambulance was on scene waiting for a patient to be brought out of the mine.
"We believe there is someone trapped ... fire are organising rescue and the Westpac Rescue Helicopter from Auckland are on the scene.
Emergency services were called at 6.35pm and the ambulance had been on the scene since 7.15pm, she said.
A Northern Fire Commuications' spokesman referred enquiries to police.