Planes good for a few years

Four of the Royal New Zealand Air Force's six Orions have flown more than 20,000 hours, giving them some of the highest flying hours in the world.

The fleet is more than 40 years old, and one plane has flown 22,623 hours.

RNZAF spokesman Squadron Leader Kavae Tamariki said the high flying hours were not a concern because the last mechanical upgrade - the 2001 Project Kestrel - extended the Orions' operational life into the mid-2020s.

He said there would come a point in time when it would not be financially viable to continue to repair the aircraft, but "we're a long way from that yet".

"The RNZAF's P3 Orions had accumulated some of the highest hours in the world fleet, and these hours were set to be the limiting factor in the life of the aircraft.

"To resolve this, the RNZAF initiated Project Kestrel to replace the wings with completely new wings," Squadron Leader Tamariki said.

This year, the Orions have been involved with numerous search and rescue missions. The most high-profile ones involved helping after the Samoan tsunami and Tongan ferry disasters.

The Orions are currently undergoing a $352 million upgrade to their navigation and communication systems.

The upgrade will improve the intelligence, surveillance and reconnaissance capability to support the government and will ensure the systems meet future regulatory requirements.