Investigators have begun their inquiry into a helicopter crash on the South Island's West Coast

Shortly before four yesterday afternoon the aircraft crashed in the town of Karamea - leaving the pilot - the only person on board, with serious injuries.

He was flown to Nelson Hospital.

The Transport Accident Investigation Commission is now looking into the incident and is asking anyone with information to come forward.

Spokesperson Simon Pleasants says they're working to gather as much evidence as possible.

He says investigators will spend the next few days in Karamea.

He says they'll talk to people who saw the crash and anyone involved with the helicopter and its maintenance.