A group of internet users calling themselves 'Anonymous' has been waging war on the Church of Scientology.

The group has launched a denial of service attack on the Scientology.org website and has published a page on Wikipedia to recruit others to the cause.

The bone of contention is the posting of an online video showing movie star Tom Cruise explaining the principles of Scientology.

YouTube and other video sharing sites removed the video at the request of the Scientologists, but one site, Gawker, has kept it online.

After threats of legal action against the site the 'Anonymous' group declared that enough was enough.

"Project Chanology was coined as a description of the 'covert' plan, the main goal of which is to enlighten the Church of Scientology by any means necessary, " the group said on its website.

"This will be a game of mental warfare. It will require our talkers, not our hackers. It will require our dedicated Anon across the world to do their part."

The group appears to have briefly taken down a Scientology site earlier in the month but there has been no official confirmation.

Scientology information website Operation Clambake condemned the attacks. "Attacking Scientology like that will just make them play the religious persecution card," said its Norwegian organiser Andreas Heldal-Lund.

"They will use it to defend their own counteractions when they try to shatter criticism and crush critics without mercy.

"I believe we are better than this cult and, face to face using democratic tools, most free and thinking individuals will see through their charade."

The Scientology movement, started by science fiction writer L. Ron Hubbard in the 1950s, has been very active in protecting its online brand and has even sued Google.