Post mortems will be held on Monday on two South African men believed to have been killed by carbon monoxide poisoning in a holiday cabin near Raglan.
Another man, 32, is in a serious condition in North Shore hospital. He was moved there on Sunday night from the Devonport naval base hospital where he received oxygen therapy.
The three were found in a unit at a motor camp at Ruapuke beach on Sunday morning.
Police say it appears they were using a charcoal cooker as a heater inside the hut.
They say the deaths highlight the dangers of charcoal burners in unventilated spaces.
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A toxicologist says the survivor is lucky to be alive.
Dr Michael Beasleyfrom the National Poisons Centre says survivors can experience neurological and heart problems and the long-term effects are not immediately apparent.