A man has been charged with sexually assaulting a five-year-old girl inside a public toilet at Orange in central-western New South Wales.

Police alleged the girl accidentally went into a men's bathroom at a park on Woodward Road on Friday afternoon.

When her mother went to get her, the child said a man had sexually assaulted her.

A 37-year-old man was arrested yesterday and charged with sexual intercourse with a child under 10-years-old.

He was refused bail and is expected to face Orange Bail Court later today.