Emergency services have resumed a search for a man who went missing on Friday evening while trying to rescue a nine-year-old boy from a dam in the state's central west.
The man tried to help the boy who struggling in the water at Wyangala Dam, about 40 kilometres east of Cowra, when he got into trouble himself.
The boy was rescued by a kayaker about 6pm but the 38-year-old swimmer was seen to "disappear underwater and not resurface", police say.
Police could not confirm whether the man and the boy were related.
Emergency services searched the river and the surrounding shoreline near the Gertie's camping area without success until 10.30pm on Friday, before the search had to be suspended.
Local police resumed their search at 7am on Saturday, with the assistance of police divers.
Gertie's camping area is described as "isolated and out of season often deserted" in the Waterways guide, which is funded by NSW Transport Maritime.
Anyone with information has been urged to contact Crime Stoppers.