Two men who were staying at a motor camp in the seaside township of Raglan have been found dead.
Their bodies were discovered just after eight on Sunday morning.
A third man was found distressed and has been taken to hospital.
He is in a serious condition and is being treated for gas inhalation.
Police say the incident is not suspicious, but have called a media conference to elaborate on the details.
It is believed a gas burner may have been responsible for the deaths.