The trend of using mobile phones to film fights outside schools, hotels and nightclubs and uploading them to video-sharing sites has concerned ACT Policing.

Videos now on the YouTube website show a teenage schoolboy being attacked, without apparent provocation, on a bus and two young boys outside a school trading blows to the head for more than a minute.

Another five-minute video called ''Queanbo boys having Fun'' features several attacks and footage of speeding cars and burn-outs.

One of the more disturbing postings features a group of young women brawling in the street outside Civic nightclub Mooseheads while an unseen male onlooker encourages the violence. ''Uppercut, uppercut,'' the unseen man says repeatedly.

''Oh yes, this is a YouTube-er, send it to YouTube.''

Three teenagers, aged 13, 15 and 16, could face charges over a video, posted on the Nothing Toxic site, of an alleged attack on a 36-year-old woman at Woden Plaza on March 31, with police awaiting advice from the Director of Public Prosecutions on whether to proceed against the trio.

Tuggeranong teenager Katie Lankuts was the victim of a bashing in the playground of her school, which was filmed and posted on YouTube, and the social networking Bebo profile of her assailant.

''It was premeditated, they brought someone especially along to film it,'' Katie said.

''The fact that it was posted and everyone saw it, not just people who were there, just added to it all, inflicted extra pain.''

Katie said that filming fights and attacks was now common among Canberra teens and she called on the owners of the websites to tackle the problem.

''There are still lots of postings, it's a widespread thing and everyone who sees a fight will film it and then post it,'' she said.

''They [the sites] should take responsibility because they're letting things like this be posted on their sites and they don't do anything until the police tell them to.''

Under ACT law, anyone posting images of an assault on the web is not committing an offence unless their purpose is to intimidate or threaten.

The websites are also operating within the law by hosting the bashing videos although YouTube, Bebo and Nothing Toxic have all co-operated with removing material when asked.

Sergeant Tim Murphy, of the ACT Policing's Crime Prevention Unit, said police expected the problem of uploading the videos to continue to grow.

''We're definitely seeing more of it,'' he said.

''It's appearing on YouTube sometimes before we even know the offence has been committed.

''With all the technology coming available, it's not something that we any control over and it's only going to be become more prevalent.''

Sergeant Murphy said it was rare for an offence to be planned just so it could be videoed.

''I know from my time in beats' patrols that when people see something going on, they just get the phone out and start filming,'' he said.

''Our experience is that people weren't necessarily trying to become involved in an offence, it's more of opportunistic thing.

''We would prefer that people who are using the phones to film incidents to use them to call the police instead.''