A YouTube video called "Fighter Paddy" has sparked outrage in Ireland as it shows an Irish child being punched in the face and kicked on the ground by cheering schoolchildren.
"Fighter Paddy" is part of a range of homemade videos which show Irish students brawling in school uniforms.
The videos have sparked fears that teenagers are being forced to take part in the fights.
The Irish school fight videos have been posted on YouTube, MySpace, Bebo and Facebook and have been viewed thousands of times.
Pip Jaffa from the Parents’ Advice Centre in Northern Ireland said such videos amount to bullying and that young people were being forced to take part.
The chilling videos are filmed on cell phones and then uploaded to the social media sites.
In the "Fighter Paddy," video, a student is shown being kicked and punched on the ground after being punched in the face. He is surrounded by jeering children and none of them offer to help.
In another video, two schoolboys appear to have been forced to fight in front of about 30 other schoolchildren.
Northern Ireland Commissioner for Children and Young People Patricia Lewsley said: “I am very concerned that young people in the area appear to be engaging in this violent behaviour. I urge the schools, parents and carers to work with the relevant local authorities to help stop this activity immediately.”
Jaffa said: “This is an unacceptable way to behave and we must get that message across to young people. This is real risk taking behaviour. It is bullying which destroys self-confidence, self-esteem and can lead to the victims suffering psychologically and even self-harming.
“So often young people believe they are invincible so we need to take action to educate them this is not the case.
“Hopefully the fact this is being raised by the media will give parents the opportunity to discuss it with their children and teach them this is wrong.”
Northern Ireland police are set to investigate the fights and the videos.
Inspector Roy Robinson said: “I will be asking for this matter to be investigated expeditiously. We will be in contact with the schools to try and identify these students as quickly as possible. If anyone can identify these young people involved I would ask them to get in contact with the police as soon as possible.”