A man has been charged with the murder of a missing nine-year-old girl.

Detectives arrested a 32-year-old man at a unit in Surry Hills last night after the child went missing from the Blue Mountains on Friday, January 14.

Police Divers, Hawkesbury Police Area Command, Public Order and Riot Squad (PORS), Operational Support Group (OSG) and Police Rescue Squad conducted a search in the vicinity of the Colo River.

The body of a child was located in a barrel but it is yet to be formally identified.