The Defence Force is sending an Air Force P3 Orion to help in the search for missing Malaysia Airlines flight MH370.
Prime Minister John Key said it left Auckland last night and was refuelling in Darwin ahead of its scheduled arrival in Malaysia this afternoon.
Read more of the Herald's Flight 370 coverage today:
• Missing plane: An 'unprecedented aviation mystery
• Lack of debris points to 'disintegration'
• Missing plane: From an acclaimed calligrapher to a young man off to begin a new career, all passengers had a story to tell
• Missing plane: Families flown to Malaysia
"The Malaysian Government has accepted the New Zealand offer to join the international search and rescue effort, and I will be talking to Malaysia's Prime Minister Najib tonight to reinforce that New Zealand stands firmly alongside Malaysia at this challenging time.
"The New Zealand aircraft will be based at the Butterworth air base in Penang along with two Australian P3 planes. They are likely to assist Malaysian authorities by searching the sea areas North of Malaysia.
"Much remains unclear about what has happened to the flight. New Zealand wants to do its part in the search and rescue effort to locate the aircraft.
"While we are aware the hope for positive news is fading, our thoughts remain with the family members of those who were on the flight, particularly the families of New Zealanders Paul Weeks and Ximin Wang.''
Flight MH370, with 239 people onboard, disappeared on Saturday morning. Among the passengers were New Zealanders Ximin Wang, 50, from Auckland and 38-year-old Paul Weeks, from Christchurch.
So far all possible leads in the hunt for the aircraft have proved false.
The oil slicks found off the coast of Malaysia during the search were not caused by the missing jet, authorities have said.
Laboratory analysis on the oil, first spotted on Saturday night, found that it had nothing to do with the Malaysia Airlines jet.
Security beefed up for Malaysia flights
Malaysia Airlines asked airports around the world, including Auckland, to beef up security screening for passengers on its flights a day after flight MH370 disappeared between Kuala Lumpur and Beijing.
Auckland Airport, the only New Zealand airport Malaysia Airlines flies to, and New Zealand's Aviation Security Service, confirmed the measures, which include extra baggage screening, were put in place on Sunday morning.
Passengers who flew out of Auckland on a Malaysia Airlines flight on Sunday afternoon had the extra checks, an Auckland Airport spokeswoman said.
"A request was made by Malaysia Airlines to put in extra security. It is only for Malaysia Airlines passengers and there have been no significant delays for check-in timing for Malaysia Airlines passengers," the spokeswoman said.
Questions about the additional security measures in place at Auckland were referred to the Aviation Security Service.
Spokesman Mike Richards said the extra security for Malaysia Airlines passengers was the result of the disappearance of flight MH370.
"There's a new layer of screening. We've got a number of measures in place to assist in providing additional security support," Mr Richards said.
The measures were taken at the request of Malaysia Airlines, which had specific requests around heightened security.
"We would work with the operator to satisfy the requirements."
Mr Richards would not say exactly what the measures were, but said one extra x-ray screening of bags for Malaysia Airlines passengers was in place at Auckland Airport.
Malaysia Airlines initially denied that it requested heightened security measures for its passengers, suggesting the Malaysian Government might have been responsible for the request.
"The airline does not have the authority to order an airport [to implement security measures]," said spokeswoman Malini Saudranrajan.
However, the airline later backtracked on the response, admitting all airports it flew to had been asked to increase security.
"Yes, it is a normal practice in the case of a crisis. Request sent to all airports that we operate in and out of," Ms Saudranrajan said.
She refused to answer further questions about the measures.