Tomb Raider has only just been released

MediaForce, based in New York, in the US, estimates that in June alone there were about one million pirated copies of movies made.

Aaron Fessler, MediaForce's chief executive said: "Online movie piracy is a very real threat to the movie production industry, especially when three of our top 10 are current, first-run production movies.

"This isn't a real abstract format where people are trading third-run movies. This is hit, current-production stuff out there and freely available in a digital format."

Other blockbuster films to feature in the top 10 are Hannibal, The Matrix, Gone in 60 Seconds, Gladiator and X-Men.

Piracy top 10

Snatch Pearl Harbor Traffic Tomb Raider Shrek The Matrix Gone in 60 Seconds Hannibal Gladiator X-Men

The MPAA has tried to take legal action to deter would be "pirates", including suing an online hacker magazine for with posting code that could theoretically be used to copy DVDs.

But some industry observers say the big movie studios add to their vulnerability by not making more of their films available over the internet.

Advances

Richard Doherty, director of New York-based technology research company The Envisioneering Group, spoke to MediaForce.

"The MPAA hasn't offered any guidelines for how movies might be paid for by subscription, so people are turning to what they can get away with," he said.

MediaForce also found movies not yet released on DVD were vulnerable to piracy.

People were said to be using digital video cameras to record films in the cinema in order to distribute them on the internet.

Pearl Harbor: Blockbuster doing well among pirates

It added that the rapid advances being made in digital technology and broadband access make movie piracy a growing problem that can only get worse.

A movie can take up to 10 hours to download using a modem and telephone modem. But a broadband connection can reduce that time to about 25 minutes.

Few homes are yet equipped with broadband technology and the medium for downloading films is still in its infancy.

But most big movie studios are working hard to build robust computer systems that allow for movies to be downloaded while maintaining strong encryption against copyright pirates.

They hope to avoid getting caught up in the same copyright infringement battle that has rocked the music industry in its legal battle with Napster.