The P8 Posideon aircraft are about the only real option to replace the P3 Orions.
The P8 is based on the very well known and proven Boeing 737-800ERX airframe which replaces the P3 Orion which was based on another passenger aircraft the Lockheed Electra. The first P8s when into service in 2013 in the US so it's a very current aircraft and used by the US and Australia.

The P3 has been around since 1960 and when it is finally replaced in 2023, the RNZAF P3s the bulk of which saw initial service in 1966 will have been in service for 57 years!!!

The moot question is whether the P8 should be weaponised given that to do so will require moving the squadron to Ohakea from Whenuapai (given that torpedo carrying aircraft really should be that near houses nor should the munitions) as this is a very costly part of the programme - and somewhat at odds with what the RNZAF actually uses the P3 aircraft currently for most of the time (SAR and Fisheries Patrol).

On the other hand, Ron Mark looked as pleased as Punch about spending money but really looked aggrieved when someone rained on his parade by asking if the aircraft were instead of paying teachers more....