Fifteen passengers were injured - four seriously - after the vehicle which was carrying predominantly British and American holidaymakers crashed in a national park on the North Island, Sky News reports.

Local media reported the bus slid 10 metres down a bank, ending up partially submerged in a stream in the Tongariro Forest Park.

One woman had to be freed from the crash wreckage by emergency services, while two people were airlifted to Taupo Hospital.

Neil Randford, National Park Volunteer Fire Brigade chief fire officer told the New Zealand Herald: "They were very lucky ... there’s been a couple of fatalities on that corner."

He described to the newspaper how the bus had landed on its side in the stream where water levels were around a foot high.

Rescue workers used a rope line to help passengers, many over them over 60, to climb up the bank to safety.

Ranford added: "They were all knocked around a bit from going down that bank ... they were all looking a bit shocked."