Graham Robb, head of the Youth Justice Board, said schools should be at the forefront of tackling the problem and needed to do more.
"Some headteachers worry that taking part in prevention activities means a school could be seen to have problems. Far from it, schools need to be involved to safeguard their pupils," he said. "There are ways to make sure young people are challenged and that orders of court are enforced. This is the tough-end stuff that needs to be done."
The call for greater involvement follows a spate of killings of school-aged children, culminating in the shooting last week of 11-year-old Rhys Jones in Liverpool. Heads in the city are expected to meet to discuss how to deal with the issue.
Mr Robb said schools did not always realise how much support was available to them from youth offending teams and the police. He told The TES that he believes schools need more training and support, not extra legal powers.
Phil Hearne, former head of the London Academy in Edgware, where Kiyan Prince was stabbed to death last year, said schools should not be afraid to use security guards and carry out weapon searches.
Mr Robb is producing guidance on how to deal with gang activity, to be published in November. It will include advice on: schools' legal powers; how they should gather information on gang-related problems; prevention work, including after-school clubs; the role of the curriculum, including citizenship and personal, social and health education; and cyber-bullying.
John Pitts, professor of socio-legal studies at Bedfordshire University, who carried out a study of gangs in Waltham Forest, north London, said mobile phones were part of the problem.
"Teachers I spoke to said school offered something of a respite from gang culture, but lessons are disrupted by texts and phone calls to do with gang activity," he said.
Mr Robb cautioned that school gang problems remained relatively rare. "The word 'gang' gives the impression of being highly organised and with criminal intent," he said. "Most groups of young people are not gangs, they are much more fluid and impulsive... We don't want to glamorise them."
Gun culture, page 4
Peter Wilby, page 17