The legislation is backed by scores of Hollywood actors, including Tom Cruise, Sharon Stone, Mel Gibson and Jack Lemon.

Offenders will face unlimited damages under the tough new paparazzi law which makes it a crime to invade the privacy of someone or their family.

Sharon Stone welcomed the new law

Photographers can be prosecuted under existing laws of trespass if they are caught on private property or if they chase or provoke someone causing fear and anger.

But damages are minimal and stars have complained there is little deterrent value.

However, the new law makes it a specific crime to invade someone's privacy by trying to videotape, record or photograph them.

The legislation has received overwhelming backing from actors' unions in Hollywood.

Arnold Schwarzenegger, Alec Baldwin and George Clooney are among the many celebrities who have clashed with the ''stalkerazzi'' in the past.

Mr Schwarzenegger - who starred in the Terminator films - says he was forced off the road when the car he was driving, carrying his two children, was chased by photographers.

Mr Baldwin punched a photographer who nearly made wife Kim Basinger drop their baby daughter Ireland, while George Clooney has had paparazzi break into his house to try to take nude photographs of his girlfriend, Celine Balitran.

But news organisations, including all the major US networks, say the new law does not make exceptions for legitimate news gathering activities.

They argue that journalists may now feel they cannot pursue certain stories for fear of prosecution.