An investigation has opened into a helicopter crash that left two dead in north Canterbury on Tuesday afternoon.
Children are believed to have been on board the helicopter when it crashed at the Kekerengu River mouth at around 12:40pm, about 60km north of Kaikōura.
Three other people were seriously injured and have been airlifted to Wellington Hospital.
The Transport Accident Investigation Commission (TAIC) says the Airbus Helicopter EC120 was travelling from Christchurch with five people on board when it lost control and crashed in shallow water close to the beach.
TAIC chief investigator of incidents Harald Hendel says he's appointed an investigation team and they are scheduled to be at the crash site on Wednesday morning.
"Their initial work will include inspecting the wreckage, mapping the site, and talking with witnesses," he said.
"Further evidence-gathering in coming weeks and months will likely include examining the helicopter's components, seeking any recorded data from the helicopter's electronics, and obtaining maintenance records."
Witnesses described seeing the helicopter spinning as it fell from the sky.
"I just saw it go down, went down, there were no explosions or whatnot but it just happened, out of the blue," a resident told Newshub.
Hendel says any witnesses to the crash, especially those who may have videoed what happened, should contact TAIC at firstname.lastname@example.org as soon as possible.
Three helicopters attended the crash, including one from Wellington, one from Nelson, and one from Christchurch, St John told Newshub. A doctor, intensive care paramedic, and ambulance were also at the scene.
TAIC said in a statement it will publish a final report on the crash, its causes and circumstances, and what can be done to avoid a similar accident happening again.
"The Transport Accident Investigation Commission opens an inquiry when it believes the circumstances of an accident or incident have - or are likely to have - significant implications for transport safety, or when the inquiry may allow the Commission to make findings or recommendations to improve transport safety."