The mother of seven of the eight children who were found killed at a home in Cairns has been arrested after receiving treatment for her injuries, Australian police said.
"The 37-year-old mother of several of the children involved in this incident has been arrested for murder overnight and is currently under police guard at the Cairns Base Hospital," detective inspector Bruno Asnicar told reporters on Saturday.
"At this time we are not looking for anybody else," he said.
Asnicar said it was too early to say how the children died, but reports have said they were stabbed to death and police confirmed that a number of weapons, including knives, were found inside the house.
The woman, who police said was the mother of seven of the children and the aunt of the eighth, has not been charged. Queensland Police said she was assisting them with their enquiries.
The deaths were reported to have been discovered by the mother's 20-year-old son who arrived at the home in the Cairns suburb of Manoora on Friday morning to find his siblings murdered.
Australian media said a woman was heard screaming and fighting with someone in the house the night before.
Candlelight vigils and church services have been held in Cairns, and police said they were working closely with the indigenous Torres Strait Islander community to which the family belonged.
"The news out of Cairns is heartbreaking," Prime Minister Tony Abbott said in a statement. "All parents would feel a gut-wrenching sadness at what has happened. This is an unspeakable crime. These are trying days for our country."
Earlier this week, a siege of a central Sydney cafe left two hostages and a gunman dead and prompted a huge outpouring of emotion.