The New Zealand Defence Force has received an early Christmas present with the arrival of the first of four new jets set to take over surveillance and transport duties in the Pacific.

The P-8A Poseidon recently touched down in Ohakea as part of a $2 billion investment into our defence capability.

The jets will be replacing the P-3 Orion, which has been a staple of the Royal New Zealand Air Force since the 1960s.

Air Vice-Marshal Andrew Clark said the P-8 will be a critical element of New Zealand's presence in the Pacific.

"We have an enormous area we have to cover. New Zealand's search and rescue region literally goes from the South Pole to the equator, half way to Australia and half way to Chile," he said.

"They'll perform a range of roles, from search and rescue to disaster relief, and possible conflict."

Four P-8s have been ordered, costing $2.3 billion – a well-timed investment as global tensions rise, according to Defence Minister Peeni Henare.

"Those growing conflicts – whether they be in Ukraine, where I've been recently, or what we see as some of the challenges in the Pacific around securing our resources and fisheries – it's important we have the kit to do that," he said.

He continued, "Our relationship with sky and sea needs to be protected, preserved and built upon, which the new P-8A aircraft will play a critical role in doing that.

"It's a milestone day and I'm proud to be here for it."

The new aircraft are expected to be more comfortable for the crew on board.

In the old P-3s, crew had to wear earplugs to block out the noise and had a bucket for a toilet. Crew members told 1News the new P-8 is much quieter and has a proper flushing toilet.