Five people have been injured after a jet boat rolled on the Rangitata River.

A Maritime NZ spokesman said a distress beacon alerted them to the incident and the Rescue Coordination Centre was activated.

A police spokesperson said police were notified at 3.15pm. 

At St John spokeswoman said they responded with two helicopters and transported five patients to Christchurch hospital; two in a serious condition, one in a moderate condition and two in a minor condition.