Children in the US could be banned from using any website in schools and libraries that allows its users to create and modify a profile, chat to other users and post personal information.

The Deleting Online Predators Act tries to limit the access paedophiles have to social networking sites, which have become hugely popular with children.

The act, which has already been approved by a large majority in the House of Representatives could affect sites social networking sites such as MySpace, Bebo, Friendster, as well as other sites like Amazon and blogs.

Critics in the US are complaining that the act is too broad and could mean a huge number of websites are cut off from users.

In both the UK and US many schools have already banned pupils from using these networks over fears that the children are taking risks with the amount of information they are posting.

The DOPA Act was introduced into the US legislative system by Congressman Michael Fitzpatrick. It passed 410 votes to 15 in a vote on 26 July.

Speaking before the vote was taken, he said: "The social networking sites have become, in a sense, a happy hunting ground for child predators".

The act covers federal institutions that received funding for computers and net access via the US E-Rate scheme - primarily schools and libraries.

If passed, the act will require organisations to put in place filters to stop children viewing social networking sites where they might be subject to "unlawful sexual advances".

The act now passes to the Senate and a vote on its approval is likely to take place in early August.