The first of two tough international internet copyright treaties come into force today.

Negotiated by the World Intellectual Property Organisation (Wipo), the treaties have already led to a series of lawsuits in the US, one of the first countries to introduce them.

A sister treaty protecting sound recordings is set to come into effect in May.

Software makers, music publishers and Wipo claim that the new rules will encourage copyright owners to put their works online by giving them clearer enforcement rights against piracy.

A Wipo spokesman said that the laws provided a platform for creators of copyrighted material to further exploit the internet with confidence.

Music industry bosses are understood to be in favour of the treaties because they provide the legal basis for record companies to introduce copy protected CDs.

But the rules have been attacked by civil liberties groups which maintain that the restrictions curb freedom of speech on the internet. While this view is undoubtedly popular it has been ignored in test cases in the US.

The courts have closed Napster, which allowed free music copying, while another case upheld an injunction preventing a hacker website from publishing or linking to software used to break encryption codes.

The European Union is expected to ratify the treaties after its member states have made enabling legislation.