A worker cutting a pipe has caused an explosion in Christchurch's Yaldhurst this morning.
Emergency services were called to the incident at a rural property on Pound Rd at 11.30am.
A Fire and Emergency NZ spokesman said a pipe being cut caused the explosion.
St John was called at 11.22am today to an incident on Pound Rd in Yaldhurst, Canterbury.
Two ambulances, a rapid response unit and a manager responded to the scene. St John treated and transported one patient in a critical condition to Christchurch Hospital.