NSW man arrested 30 years after assaults

A 51-year-old man has been charged over child sexual assault allegations dating back three decades as NSW detectives appeal for more victims to come forward.

Police first became aware of the allegations in 2009 when two women claimed to have been abused in the late 1980s and 1990s.

The man was known to the victims and the alleged offences occurred in the Penrith area, police said on Tuesday.

Three men later alleged they too had been sexually assaulted in the same period.

The 51-year-old was arrested at a caravan park in Mudgee, in NSW's central west, on Tuesday morning.

He was charged with 19 offences including aggravated sexual assault and aggravated indecent assault and is due to appear before Mudgee Local Court on Wednesday.

"Police believe further offences may have been committed in the Penrith area, as well as the Mudgee area, where the man has resided for an extended period of time," police said in a statement.