A former Liberal Party staffer, who has worked in the offices of two NSW premiers, has been arrested on historical child sexual abuse charges after a four-year investigation by police.

The 41-year-old man, who cannot be named as he was a juvenile at the time of the alleged offending, was charged on Tuesday with a number of offences against two children who knew him.

"Police will allege in court that the man sexually and indecently assaulted a boy and a girl – aged between eight and 10 – while they were in his care between July 1994 and December 1996," a NSW Police spokesperson said.

The man was charged with three counts of Raggravated indecency against a victim under 16 and under his authority, two counts of sexual intercourse with a person aged 10-16 and under his authority, and one count of attempted sexual assault with a person aged 10-14 and under his authority.