Three adults charged over NSW kid bashing

The savage bashing of a four-year-old Sydney boy has led to the arrests of the three adults responsible for taking care of him.

The boy suffered brain haemorrhages, multiple bone fractures, a broken tooth and severe bruising after he was allegedly beaten by the three adults on May 26.

He was taken to Westmead Children's Hospital, which alerted NSW Police.

Detectives from Penrith's Child Abuse Squad on Tuesday charged two women, 36 and 28, and a man, 26, with the assault.

Police allege the boy had been subjected to ongoing, systematic physical abuse at a Doonside home in Sydney's west.

The three carers have been charged with reckless grievous bodily harm and hiding the offences, and have been refused bail.