A Western Australian man has been charged with aggravated assault after allegedly using cable ties to restrain three children.
Police said the man had detained the six-year-old girl and two boys aged seven and eight after finding them swimming on a vacant property.
Video circulated online appears to show two of the children tied up and crying.
Top state officials say they are "appalled" by the footage and police have called for calm in the community.
Authorities said the 45-year-old man had called them on Monday to report the incident in Broome, about 2,000km (1,200 miles) north of Perth, telling them he had found the children in an "unoccupied pool".
Officers arrived to see two children "physically restrained" with cable ties and later found the oldest boy who had fled the scene, WA Police said.
Footage shared widely online shows two children - who appear to be Indigenous - in a driveway, while onlookers urge a man, who is white, to let them go.
Paramedics assessed the two children at the scene and they were reunited with their families shortly after, according to authorities.
Police said the "force used to restrain" the three children "was not proportionate" given their age and vulnerability.
The state's children's commissioner, Jacqueline McGowan-Jones, said she was disturbed by the footage.
"It would appear these are very young and small children. They appear to be quite frightened in the circumstances. He is quite a large man. And they appear to be very nervous," Jacqueline McGowan-Jones told the Australian Broadcasting Corporation on Tuesday.
"They don't have the neurodevelopment to understand cause and effect and consequences and actions. And that is legally known," she added.
The man has been granted bail and is due to appear before the Broome Magistrates Court on 25 March.
According to recent government data, Indigenous Australians aged 10-17 are 29 times more likely than non‑Indigenous children to be in detention nationally. Ten is the minimum age of criminal responsibility in Western Australia.
