Police are responding to a workplace incident on Chapmans Boundary Road in West Eyreton.

A Police spokesperson told Chris Lynch Media one person has been seriously injured.

St John was notified at 12.17pm, and responded by sending a helicopter, two rapid-response vehicles and one ambulance.

 One patient has been airlifted to Christchurch Hospital in a critical condition, a spokesperson confirmed.

WorkSafe has been notified.