A man injured in an explosion last night has serious burns to the top half of his body, including his face.

A Fire and Emergency services spokesman said there had been an explosion and fire in a coal hopper, which was put out at about 9.30pm yesterday.

Westpac Helicopter intensive care paramedic Casey Drum said the helicopter reached the patient, who had been transported to Bay of Islands Hospital by St John Ambulance, at around 9pm last night.

He said the man was transported to the National Burn Centre at Middlemore Hospital "because of the severity of his burns". The flight took just under an hour.

Drum said the man had "fairly serious burns to the top half of his body", including his face.

He said the man was in a lot of pain with the burns, but did not suffer any other injuries.

A Worksafe spokeswoman said Worksafe had been notified of the incident and had opened an investigation.

Two Worksafe vehicles were parked at the plant this morning.