GardaÍ are trying to identify a man known to be targeting and sexually harassing women on Dublin's buses.

The man is thought to be in his late 30s and is understood to be non-Irish. A photo-fit of the man has been released to all garda stations across the country, and may be released to the public as the investigation develops.

In one recent incident, a man approached a female passenger who was sitting on the top of the 19A bus and proceeded to hem her in to the inside of the seat. The bus was almost empty at the time of the occurrence. He proceeded to cover himself completely with his coat and attempted to begin touching the woman.

Gardaí also understand he was performing a sexual act on himself under the coat during the ordeal, which lasted a few minutes. The man was confronted and threatened by another passenger on the bus who is also being sought in the investigation. During the confrontation, the offender fled the scene at Phibsborough.

The driver was alerted and the CCTV footage from the bus was pulled. It will now form a pivotal part of the investigation over the next few weeks. The footage shows the entire incident and sees the man follow his victim up to the second floor of the bus where he proceeds to carry out his lewd act.

A statement was subsequently made to gardaí about the incident. According to one garda involved in the investigation, "there are very clear photos which were taken from the footage which make us more confident that he will be caught over the next short while".

According to another garda source: "This is not the first time we have come across incidents of this nature, especially on Dublin Bus. There is currently another investigation into the same type of incident in which the offender is only now coming to be questioned because this type of investigation takes a lot of time".

When queried about exactly how many events of a similar nature have taken place on Dublin buses, spokeswoman Maria Brennan said: "As this incident relates to a specific case which is now part of a criminal investigation, it would be inappropriate for us to comment at this time."

In 2003, gardaí launched a similar investigation to catch a man who repeatedly assaulted women on Dublin buses, subjecting them to terrifying sex attacks and exposing himself to them. Numerous women reported the ordeal at the time and the man was subsequently caught by investigating officers.