The discovery of the bodies added to a traumatic week for Australia after a deadly hostage-taking in Sydney only days ago
Police said they were called to the property in the Manoora area of Cairns on Friday morning after reports of an injured woman.
"During an examination of the residence, police located the bodies of the children, all aged between 18 months and 15 years," the Queensland Police Service said in a statement. The horrendous scene had been discovered by a 20-year-old brother of the children.
Police so far have no formal suspects in the case, said Detective Inspector Bruno Asnicar, but he sought to allay fears among local residents about the deaths.