KEY POINTS:
A contractor who helped to repair a major gas leak on the North Shore died at the scene in his work van.
A witness said the man was not wearing breathing apparatus while working on the leak. The Department of Labour is investigating whether the incidents are linked.
The man was found by a roadworker on Glenfield Rd yesterday morning in the front seat of his Ace Gas Maintenance van with his seatbelt on.
Police on Monday cordoned off several streets after a high-pressure main supply pipe was ruptured, possibly by contractors working in the area.
Ace Gas was called to repair the damaged pipeline.
The roadworker said he had seen the man, reported to be aged in his mid-40s, working on the pipe in a hole in the ground.
Police on Monday advised residents near Glenfield and Manuka Rds to stay in their homes and keep windows and doors closed to avoid breathing in fumes while the gas was dispersed by the wind.
However, firefighters investigating the leak said evacuation was not required.
A spokesman for Ace Gas said last night that the man's van had been parked outside the police cordon on Monday night so two of his colleagues drove him to the vehicle after they had all finished working on the leak about 9.30pm.
He said the man told his colleagues he would drive straight home but it appeared he had only managed to drive a few metres.
"He was on his way home, he pulled over. He must have realised something was wrong."
The spokesman said he thought the man had died of a heart attack.
"The death had nothing to do with the gas whatsoever."
A blue tarpaulin was draped over the front seat of the van covering the body yesterday.
Police northern communications centre section manager John Fraser said police spoke to the man's colleagues who turned up in the morning, neighbours and other witnesses.
"He had been strapped in the driver's seat all night. There were no suspicious circumstances."
A post mortem examination was carried out at Auckland City Hospital yesterday, Mr Fraser said.
A St John ambulance attended about 9am and declared the man dead at the scene.
A Department of Labour spokeswoman said inspectors were investigating.
"We are working to identify if this was a workplace death.
"Sometimes we discover the person may have died of natural causes, like a heart attack. But sometimes it's not obvious."