Seven people, including four children, have been found dead in a rural town in the Margaret River wine-growing region of Western Australia.
The bodies of four children and three adults were found at or near a property in Osmington near the southwestern tip of Australia, Western Australia's Commissioner of Police Chris Dawson told a news conference.
"I can only describe it as a horrific situation," he said.
"We have no information to raise concern about wider public safety issues at this point in time."
Police say at least some of the victims had suffered gunshot wounds.
Gun crime in Australia fell sharply after strict controls were introduced in response to a mass shooting in 1996, when a lone gunman killed 35 people in Tasmania.
That prompted the government to buy back or confiscate a million firearms and make it harder to buy new ones.