At least two pilots are believed to have died in a mid-air collision near Masterton on Sunday morning.
Emergency services were called to the scene after two light aircraft crashed near the Hood Aerodrome at around 11am.
Skydive Wellington has confirmed one of its planes was involved, and the Wairarapa Aero Club (WAC) says a pilot with two years' experience was flying the other.
The accident is believed to have happened in uncontrolled airspace as both aircraft were on final approach to the Hood aerodrome runway.
"They were unsighted to each other and collided mid-air, we believe both pilots are dead," says WAC chief flying instructor Robert Thurston.
The WAC plane was a Tecnam Sierra 2 seater and was one of their training planes.
Police say more information will be released as it becomes available.
The Civil Aviation Authority has been notified will be investigating.