A New Zealand deerhunter who was stranded for five nights in a freezing forest was kept alive by the warmth from his pet dog.

Desmond Pemberton fell into a ravine after crashing his jeep in the Kaimanawa Forest.

The 58-year-old is in remission from lung cancer and suffers from emphysema. He was found frozen and unable to speak.

He is reported to be in a critical condition in Rotorua Hospital.

Rescuers say he would not have survived another night in the open.

They believe Mr Pemberton was prevented from dying of exposure by will power and warmth from his Labrador dog B, who slept alongside him at night.

Temperatures fell to minus four degrees. Senior Constable Barry Shepherd said Mr Pemberton was found suffering from hypothermia.

Senior Constable Shepherd told the New Zealand Herald: "We're actually quite amazed he's still alive."

Lance Keightley, who helped load his friend into a rescue helicopter, said: "He was that cold he was actually stiff. He couldn't open his mouth."