Mystery around NSW fatal plane crash

Mystery surrounds the circumstances of a fatal plane crash in northern NSW which killed two men after the aircraft plummeted to the ground about 80km off course.

The aircraft burst into flames when it crashed into a paddock off the Bruxner Highway in South Gundurimba, south of Lismore, at 12.15pm (NZT) on Friday.

Two men, believed to be a 47-year-old and a 40-year-old from the Gold Coast, died at the scene.

The crash sparked a grass fire and debris was strewn around the wreckage.

"There is a large debris field of about 50 metres in length," a Fire and Rescue NSW spokesman told AAP.

It is believed the Socata Trinidad took off from Gold Coast Airport about 11.30am and was heading south to Murwillumbah Airport.

A focus of the investigation will be how the plane ended up in South Gundurimba, about 80km south of Murwillumbah.

Police from Richmond Local Area Command, crime scene officers, as well investigators from the Australian Transport Safety Bureau, remained at the scene on Friday evening.

The cause of the crash was not yet known, but one witness told the Seven Network the plane banked hard left, then "fell like a rock" to the ground.

- AP