Police have confirmed that two people have died following a crash involving a small plane at Te Kopuru in Kaipara District this afternoon.

Emergency services were called to the scene shortly after 12.15pm.

The scene is being examined by the Serious Crash Unit and the crash will be referred to the Civil Aviation Authority and the Coroner.

Witnesses reported seeing debris fly off the northward-bound plane about a kilometre before it plunged into a paddock alongside the Northern Wairoa River.

Police and emergency services are on-site.

The Civil Aviation Authority (CAA) is launching an investigation into the fatal crash.

CAA spokesman Mike Richards said it is too early to tell what may have caused the accident but they are deploying two safety investigators from Wellington to start the investigation.

"They will first meet with Police and speak with emergency services who attended the accident.

"The safety investigators will review any photographs taken at the scene at Te Kopuru in Kaipara District, they will also arrange to talk to any witnesses.

"The CAA investigators will arrive on Tuesday 2 January," Richards said.

There will not be any further updates until the investigator in charge has completed a site visit, this is likely to be sometime on Tuesday afternoon.

The aircraft type was a Rans microlight RV 7.

The CAA would like to speak to anyone who may have witnessed the accident.