The Defence Force could buy four new Boeing aircraft from the US for nearly $1.5 billion.
The US department of defence has announced it may sell the New Zealand Defence Force (NZDF) four new Boeing aircraft at a cost of nearly $1.5 billion.
But the Defence Force said the government had not yet committed to any sale.
The US said New Zealand had asked to potentially buy four P-8A Patrol aircraft, equipped with commercial engines, missile warning sensors, infrared and laser transmitter assemblies.
They will replace the Defence Force's current fleet of P-3 Orion aircraft. The $1.47bn price included training and assistance, technical services, and repair.
New Zealand First leader Winston Peters said he was concerned the reduction from a fleet of six to four would cut the country's patrol aircraft by a third.
He asked how four aircraft could cover the area New Zealand is responsible for, which extends from Antarctica to north of the equator and from the mid-Tasman Sea to east of the Cook Islands.
Mr Peters said there should be competition between Boeing and other companies.
The US defence department said the sale would strengthen collective defence, and enhance New Zealand's allied contributions.
But a spokesperson for the Defence Force said the US announcement was a non-binding part of the process and it was legally bound to inform the public.
The spokesperson said the price was higher than it expected to pay and the offer would be considered over the next couple months.
In June last year, the government announced it would spend $20 billion on the Defence Force in a long-term investment plan that also includes a new cyber security system for defence networks.
It detailed plans to replace the Air Force Boeing 757, the C130-Hercules, the Orion maritime patrol aircraft and the ANZAC frigates, over the next 15 years.