Police officers inspected cars involved in the crash, which happened about noon on State Highway 79 between Geraldine and Fairlie, when the two cars collided head-on on a bend.
Geraldine Volunteer Fire Brigade chief Graeme Mould said the female tourist who died was in a car with two other people who were not able to speak English to emergency services.
He said a group of paramedics from Western Australia had been travelling through the area at the time and were first on the scene; they commenced first aid before emergency services arrived.
A male and female tourist were flown to Christchurch Hospital with serious injuries, while another man was taken to Timaru Hospital by ambulance with moderate injuries.
A section of the highway was closed while emergency services investigated and cleared the scene.
Police said names would not be released until next of kin had been notified.
By Alexia Johnston, with additional reporting by APNZ.
