Investigators would return to the property on Monday, with a lot of work to do to determine what happened, Detective Superintendent Danny Doherty told reporters.
“However, at this stage, it does appear that the 28-year-old man is responsible for multiple deaths of young lives that have been tragically taken away,” he said on Sunday.
Detectives are treating the incident as a domestic-related multiple homicide, he said.
Attempts to enter the burning home were allegedly met with resistance as police officers and a neighbour heroically tried to rescue children from the fire, acting Superintendent Jason Pietruszka said.
“I can confirm during police attempts to get into the property, those efforts were frustrated by a male inside.
“That male has been arrested.”
Their efforts prevented the loss of more lives, he said, but the fire and the death of three children would have a long-lasting impact.