A 68-year-old Korean tourist collapsed and died while tramping Fiordland's Milford Track.
Emergency services were contacted by a guide about 11.30am on Saturday when the man collapsed.
Sergeant Tod Hollebon of Te Anau police said the guide carried out CPR for some time.
A rescue helicopter with a doctor and police search and rescue personnel flew to the scene from Te Anau, but the man was pronounced dead on their arrival.
Mr Hollebon said low cloud at McKinnon Pass where the incident happened made access more difficult, however it did not affect the ability of the medical team to attend.
Police were working with the Korean Embassy to inform family members back in Korea, he said.
There were no suspicious circumstances to the death and the matter had been referred to the coroner.