Two men found dead in a Coromandel mine tunnel died of carbon monoxide poisoning from their petrol powered generator, say police.

The two Whitianga men were 40-year-old Kerry Alexander Murphy and 49-year-old Grant Christopher Wylie.

Two men found dead in an abandoned mine tunnel in the Coromandel died from carbon monoxide poisoning from a petrol powered generator.

Thames Coromandel CIB Acting Detective Senior Sergeant Ross Patterson says the cause of death was obtained from a post mortem examination conducted in Auckland today.

"Police and ESR forensic specialists removed a significant amount of equipment and chemicals from near the scene yesterday and these items have been confirmed as being consistent with a clandestine drug laboratory,” says Ross.

"The inhalation of chemicals fumes from the clandestine laboratory has not been discounted at this stage and the cause of death will be determined by the Coroner."

The two men were found dead in the old mine tunnel off the 309 Road about 10km from Whitianga on Saturday.

Police, working through difficult terrain, removed the pair's bodies yesterday for transportation to Auckland for this morning's examination.

"There's been a lot of speculation about what happened, however at this time I can confirm there was no explosion in or around the mine.

'This investigation is being treated as sudden deaths as opposed to a homicide inquiry and we are not looking for anyone else in connection to the deaths.”

The weekend's double tragedy shows the inherent risks to life of operating petrol powered engines such as generators in confined spaces, says Ross.

People must exercise the utmost care and diligence in operating these machines says Ross.

"This is another case that shows the risks to people's lives when they dabble in the manufacture of controlled drugs such as Methamphetamine. People need to realise that cooking controlled drugs poses a high risk to themselves and others around them.

"In addition to that, in this case the question has to be asked where were the volatile waste materials associated with the manufacture of this drug being dumped. These waste products are highly toxic and pose a risk not just to people's health but to the environment as well."

Anyone with any information on illegal drug manufacture is asked to contact your nearest Police station- your call will be treated in confidence, alternatively information can be left with Crimestoppers on 0800 555111.