Police arrested a man in Werribee South yesterday in relation to a sexual assault investigation.

The 29-year-old from Lakemba, in New South Wales, was charged with sexual penetration of a person under 16.

Police said the charge related to an incident in December last year.

The man was remanded to appear in the Melbourne Magistrates Court tomorrow.

Earlier this month, two other men were arrested as part of the same investigation.

A 23-year-old man from Werribee was arrested on January 8 and charged with sexual assault of a child under 16, sexual penetration of a child under 12 and sexual penetration of a child under 16.

He was remanded to appear at the Melbourne Magistrates Court on May 6.

A 21-year-old man from Noble Park was arrested on January 12 and charged with sexual assault of a child under 16, sexual penetration of a child under 16 and sexual penetration of a child under 12.

He was remanded and is expected to appear in the Melbourne Magistrates Court tomorrow.