NSW toddler dies in hospital

A three-year-old boy who was seriously injured at his home in the NSW Central Tablelands has died.

Police were called to a home in Oberon on Sunday afternoon where the toddler was unconscious and not breathing.

Officers performed CPR before the boy was flown to a Sydney hospital in a critical condition.

He died in hospital on Wednesday night, police say.

Officers have established a crime scene at the Oberon home in Cunynghame St, where the boy lived with his stepfather, mother and adult brother.

Strike Force Aldyth has been established to investigate the death, police say.

Detective Inspector Luke Rankin said police were told the child was injured after being knocked over by one of the family's dogs at a park.

"That's one of the lines of inquiry we're following up in our investigation," he told the ABC.

The park is across the road from the family's home.

A report will be prepared for the coroner, police said.