Westminster City Council is planning to watch over social media activities of those suspected of unlawful behaviour as part of a 180,000 project, according to a report.
A private council document reportedly seen by The Times showed information of potential troublemakers would be gathered from sites like Facebook and Twitter.
It comes as part of a push to crack down on youth violence and vandalism, following the London riots in August.
... it would be a gross abuse of the relationship between social workers and young people, and a serious invasion of privacy.
Westminster Council said it wants to "spot confrontations" by watching over social networks as part of a three-year project, the document showed.
The council is also reportedly considering using social sites to warn potential lawbreakers that they are being watched.
Nick Pickles, director of the Big Brother Watch, was concerned that the reports indicated social workers who were part of networks would be expected to pass on any relevant information they had.
"If this were the case, it would be a gross abuse of the relationship between social workers and young people, and a serious invasion of privacy. Furthermore, it would only exacerbate the mis-trust between young people and the authorities at a time when we can ill afford to do so," Pickles said in a blog post.
"Councils should not be seeking access to private communications and personal data when they have little justification for doing so or without the approval of a court. If crimes are being committed, it is the job of the police to investigate local councils have no role in spying on citizens in this manner."
At the time of publication, Westminster Council had not replied to a request for comment.
The Government recently held talks with representatives of social networks, including Facebook.
Whilst they discussed whether social networks could work in closer alignment with police, without apparently talking about restrictions on such services, privacy groups raised concerns over greater Government control over the public internet.
Human rights bodies felt compelled to write to the Coalition, warning of the dangers of banning people from social networks if they are deemed to be a danger.
