DNA samples belonging to children who commit sexual and violent offences could be kept by the police under a review of the law surrounding DNA retention launched yesterday.

The Scottish Government has asked a senior forensic expert to look at whether samples should be retained from young sex and violent offenders who go before children's panels. Currently, police are only allowed to store the DNA of children who are convicted of violent or sex crimes in an adult court. The proposal has already worried some human rights activists.

The government review will be carried out by Professor James Fraser, the head of Strathclyde University's Centre for Forensic Science.

Scotland has already rejected proposals to create an English-style national DNA database. Police forces in England and Wales are believed to have kept the DNA of more than 100,000 innocent children.

Kenny MacAskill, the Justice Secretary, said the government wanted to strike a balance between the rights of citizens to privacy and the best possible protection from criminals.

He said: "We recognise there remain differences of opinion and we believe there is merit in examining whether there are further changes to the regime that we can ask parliament to consider.

"Our government has already made clear we do not support the blanket retention of all forensic information taken from innocent people. We are not persuaded, for example, that it would generally be right for the police to keep fingerprints and DNA samples from everyone who is detained but not eventually convicted, or even prosecuted.

"The new review will focus on individuals who are prosecuted for violent and sexual offences, and examining why it should be lawful to allow DNA records to be retained but to require fingerprint records to be destroyed.

"We have also asked Professor Fraser to review previous decisions to continue requiring the destruction of all forensics taken from youths who admit or are found to have committed sexual or violent offences, and who may therefore pose a future risk to others and perhaps to themselves, where they are dealt with through the Children's Hearing system rather than in the criminal courts."

John Scott, head of the Scottish Human Rights Centre, said he believed the proposals were worth examining, but warned keeping DNA samples could brand youngsters as offenders long after they leave the children's hearing system. "Perhaps we should consider the length of time for which such samples can be kept," he added.

Helen Wallace of Genewatch, a group which campaigns against the blanket retention of DNA, said she was relaxed about DNA profiles being kept of juveniles who had committed serious offences. She said: "If such a proposal is to be considered it would have to be justified by evidence that it is likely to prevent serious crimes."

Authorities in Scotland are only allowed to store permanently the DNA of people convicted of crimes. They can, however, also keep the DNA of those charged with, but not convicted of, serious sexual and violent offences, but only for three years unless a sheriff agrees to extend the period.

Police may also keep the DNA of those involved in investigations, but only until the investigation is concluded.