A 28-year-old man and a 15-year-old female attended a unit in Wollongong in March where the girl was allegedly sexually assaulted.

Police allege the man also exposed himself to a number of young children at a park in March.

The man was charged with aggravated sexual assault, commit act of indecency (towards children under 12 years), convicted child sex offender loiter in public place and breach of bail on Wednesday.

He was refused bail to appear in Wollongong Local Court on Friday.