A truck driver blew up like a human balloon when compressed air was forced into his body in a bizarre accident.

Steven McCormack, 48, of Opotiki, fell on the "nipple" nozzle of a compressed air reservoir powering his truck's brakes on Saturday.

The nozzle pierced his left buttock and the air, compressed to 100 pounds per square inch, began rushing into his body and he started screaming.

Despite his bad luck, a cheery Mr McCormack told his story from his hospital bed.

"I felt the air rush into my body and I felt like it was going to explode from my foot.

"I was blowing up like a football ... It felt like I had the bends - like in diving. I had no choice but just to lie there, blowing up like a balloon."

Doctors later told him that the air separated fat from muscle, and were surprised it did not break his skin.

He said afterwards his skin felt "like a pork roast" - crackling on the outside but soft underneath - and the only way for the air to escape was the usual way gas passed from the body.

Mr McCormack's workmates at Waiotahi Contractors heard his screams and found him with the gadget hooked into his rear, company co-owner Robbie Petersen said.

He said he could hear the air hissing out and quickly released the pressurised container's safety valve to stop the air flow.

The nipple remained embedded as three men - Jason Wenham, Ross Hustler and Mr Petersen - lifted Mr McCormack's upper torso.

Mr Wenham put him on his side in the recovery position, a move Mr McCormack thought probably saved his life.

It helped him breathe, although his head and neck were swollen and one lung was filling with fluid.

His workmates broke into a water-cooler to find ice, which they packed around his neck to ease the swelling.

They waited an hour for ambulances to arrive from Whakatane, as Opotiki's ambulance and the rescue helicopter were busy.

Aided by a doctor, ambulance officers removed the nipple and Mr McCormack was taken to Whakatane Hospital.

Doctors inserted a tube into his lungs to drain the fluid and cleared the wound in his buttock using what felt to him like a drill. "That was the most painful part."

He told Campbell Live the process of removing the gas took about three days and involved "burping, farting and things you are not meant to be doing while people are around".

He said he knew what was happening to him when he was filling up with air and was "almost crying". He was also conscious of how he appeared: "The people wouldn't come near me because of what they could see. It wasn't a very nice sight.

"I looked like the Michelin Man."

Mr McCormack credited his workmates - Mr Wenham especially - with saving his life and thanked emergency services and hospital staff.

Mr Petersen said it was a "million-to-one freak accident" and he had notified the Department of Labour. NZPA, Whakatane Beacon