UPDATE - A rescue helicopter winched three crew from a liferaft to safety today after they had earlier abandoned their blazing fishing boat 100 nautical miles off Cape Reinga.
The rescue happened at about 10.20am.
An Air Force Orion had earlier found a lifeboat with the three crewwho had abandoned their boat.
A crew member made a distress call to Maritime Safety Authority's maritime operations centre about 4am.
He managed to give the boat's location but communication was cut off and no contact has been made since, a Rescue Coordination Centre New Zealand (RCCNZ) spokesman told NZPA.
The Orion tracked the boat by its emergency locater beacon about 8am and would guide a helicopter heading to the lifeboat to pick up the crew, he said.
The condition of the crew was not known.
"We haven't heard from the crew since the first call. If the fire was bad they may have had to leave the fishing boat and their radio and use a lifeboat," RCCNZ spokeswoman Heidi Brook told NZPA.
It was believed the crew had abandoned the fishing boat's wheelhouse because of the fire.
"We assume they don't have a hand held VHF radio on the lifeboat," RCCNZ spokesman Lindsay Sturt said.
The Orion took off at 7am for an area northwest of Cape Reinga to pinpoint the boat for the Westpac rescue helicopter, which left Auckland at 6am.
The helicopter, which is slower than the Orion and has more limited range, was due to refuel at Te Paki Station near Cape Reinga before rescuing the crew.
A commercial vessel heading to the lifeboat was expected to arrive about midday.
RCCNZ search and rescue officer John Ashby said weather conditions were reasonable with a 10 knot southerly and a 1m swell.
"It's a difficult rescue as they're so far out at sea and there aren't any available vessels in the area which can help.
"We're pleased they were able to make a short call to us when they did as it meant we could get rescue teams out to them quicker."
The name of the boat and its crew would not be released until their families had been informed, Ms Brook said.
