Fortitude Valley detectives are investigating an alleged indecent act which occurred on a north Brisbane train in early November 2019.

Shortly before 5.30am on Saturday, November 9, a man entered a north Brisbane bound train at Bowen Hills sitting opposite a 19-year-old woman.

The man then allegedly committed an indecent act.

He moved away when the woman confronted him exiting the train at Eagle Junction Railway Station before boarding another training and exiting at Nudgee Railway Station.

The woman was not physically injured.

If you have information for police, contact Policelink by providing information using the online suspicious activity form 24hrs per day at www.police.qld.gov.au/reporting.

You can report information about crime anonymously to Crime Stoppers, a registered charity and community volunteer organisation, via crimestoppersqld.com.au 24hrs per day.

Quote this reference number: QP1902308677 within the online suspicious activity form.