A New Zealand man has been decapitated in front of his family while taking a homemade hovercraft on a test run.

Police said the 40-year-old, whose name has not been released, died instantly when he was struck by a propeller blade while using the hovercraft at Muriwai beach, west of Auckland, on Sunday, the New Zealand Herald reported.

The newspaper said it was the first time the man had driven the hovercraft, which he had assembled from a kit.

Fairfax Media said police planned to interview members of the man's family about the death.

"Some of them were present on the beach," Sergeant Colin Nuttall told Fairfax.

The report said an engineer was examining the remains of the hovercraft and the death had been referred to the coroner.

Sergeant Nuttall told the Herald that New Zealand did not have regulations covering recreational hovercrafts, provided they were not used on roads.

AFP