The 65-year-old man who died following an industrial accident near the Homer Tunnel in Fiordland this afternoon was clearing a slip at the time, police say.
At about 12.50pm a worker for a contract company was killed while clearing a slip near Monkey Creek on the Milford Road, Te Anau Police Sergeant Tod Hollebon said.
The man sustained a "very serious head injury" following an incident with a compressed air hose, Southern ambulance spokeswoman Alena Lynch said.
He was treated at the scene by St John paramedics who had flown to his aid in a rescue helicopter from Te Anau, she said.
Despite the best efforts of all those on site, he was unable to be revived, Mr Hollebon said.
Two other workers also received minor injuries in the incident and were treated at the scene.
Occupational Safety and Health are investigating the incident along with a safety representative of the contract company.
Police will also be investigating on behalf of the coroner, Mr Hollebon said.
The accident is understood to have involved equipment being used on site at the time, however the details of the incident have not yet been established, Mr Hollebon said.
Police are in the process of contacting the man's next of kin.