A 30-year-old Casey man faces court after allegedly committing an indecent act on a bus in the presence of a teenage girl.

On the evening of January 14, a teenage girl passenger noticed a man sitting nearby allegedly committing an indecent act.

Police say the teenager captured the incident on video and the matter was reported to police that evening.

Police also obtained CCTV footage from the bus of the incident and searching for the man.

On Wednesday night police were called to the Gungahlin Marketplace following reports that a man was looking into change rooms in a store.

The man was identified using CCTV footage from the January 14 incident and he was arrested. He has been charged with committing an act of indecency on a person under 16 years.