Rescue crews converged on a remote South Island mountain range after a report of a plane crash near Murchison following a mayday call shortly before 4pm.
Details remain scant but a Rescue Coordination Centre spokeswoman confirmed a response was being coordinated to the crash near Murchison, understood to be in the Braeburn Range, just west of Lake Rotoroa in the Nelson Lakes region.
"A helicopter is on scene and EMS helicopters are enroute as well," she said.
"Bystanders with cellphone coverage have been asked to facilitate a video conference assessment with emergency services, and the passengers will also be assessed on scene once the medical personnel arrive."
Shortly after 5pm the spokeswoman said two rescue helicopters, from Garden City Nelson and Garden City Greymouth, were both on the scene.
There are reports of serious injuries and two people will be taken to hospital, she said.
A man working at Murchison Helicopters said he understood the occupants had survived the reported crash.
"They're alright," he said.
A police spokeswoman said they were aware of the mayday call but their services were not required at this stage.