Each tourist belonged to Switzerland and Denmark. The aircraft was carrying six tourists when it crashed on Tuesday afternoon off Rottnest Island, a popular tourist destination around 30 km (18.6 miles) west of Perth. The three surviving tourists were injured, Reuters reported.

"My thoughts go out to the families and friends of the victims. This is no doubt very difficult for everyone involved," Western Australia s state Premier Roger Cook told a news conference.

The crash occurred in front of holidaymakers, including families with children vacationing on the island, Cook added.

The state s police commissioner Col Blanch said authorities had begun an investigation into the causes of the crash.