The Home Office is investigating a website that publishes the home addresses and telephone numbers of anti-racism campaigners, politicians and journalists.
Anti-Nazi League protestors have been targeted by Redwatch
The website, Redwatch, publishes photographs and contact details of individuals under the slogan "Remember places, traitors' faces, they all pay for their crimes".
A Home Office spokeswoman told BBC News Online "We are aware of the anxiety caused by the presence of such material on the internet"
"We have had representations from many MP's about this matter and will be responding to their concerns very soon."
One of the Redwatch internet domain names is registered to the National Front.
A spokesman for the NF said "we are a law-abiding political party and have nothing to do with Redwatch or its owners".
Anti-fascist campaigners Searchlight believe Redwatch could be prosecuted under legislation covering incitement to racial hatred.
Liberal Democrat peer Lord Greaves has raised the issue in the House of Lords and believes that there is a need for legal action.
"We need to test existing legislation to prosecute these people and if it's not strong enough we need new legislation.
"There's a great reluctance by the police to prosecute anyone under incitement to racial hatred legislation as some tabloid newspapers might fall foul of it.
"I think that politicians and the police need to stand up to these people."
The Home Office argues that as the material is hosted by computers outside the UK, where British police and courts have no jurisdiction, there is nothing that can be done under current legislation.
It also argues that if hosted in the US, such material would be protected by the first amendment, that guarantees the right of freedom of speech.
Since raising the issue, Lord Greaves has had his picture posted on Redwatch.
Photographer David Hoffman has been taking pictures of racist groups at demonstrations for 25 years.
Soon after his details were published on Redwatch, he began to receive menacing phone calls.
"People started phoning me and saying 'we're going to kill you' and that sort of thing.
"To be honest, I wasn't that worried as I thought that if someone was going to kill me, they wouldn't call me and let me know first."
Hoffman was concerned enough, however, to have a "firebomb-proof letterbox" and bullet-proof window glass installed.
Despite the threats, police told him there was not much chance of gaining a conviction against the callers and that there was little they could do.
Freedom of speech
Comedian and activist Mark Thomas has also been featured on Redwatch but believes that the website is the work of a few extreme individuals rather an organised campaign.
"I believe that some of the people who put this stuff up there are actually mentally ill.
"I get strange phone calls everyday but nothing threatening - I refuse to get wound up by it and just get on with things."
Thomas is wary of pursuing calls for legislation to tackle Redwatch as he is concerned about any new laws that curb freedom of speech.
"We need the Home Office investigation to find out whether there is a direct correlation between these calls and Redwatch before we act"