Cambodia has deported a Swedish founder of the popular file-sharing site The Pirate Bay who is wanted in his homeland for copyright violations.

Gottfrid Svartholm Warg was put aboard a Thai Airways flight on Monday night, said Chhay Bunna, a senior police officer in the immigration office at Phnom Penh's international airport.

He said Cambodian authorities handed Svartholm Warg over to two Swedish police officers who were waiting at the plane's door.

Svartholm Warg was arrested on September 2 at his rented apartment in the Cambodian capital at the request of the Swedish government. He was not made available to journalists after his detention.

A team of Swedish officials visited Phnom Penh days after his arrest and presented legal documents on the copyright infringement case against him, National Police spokesman Kirth Chantharith said earlier.

Cambodia has no extradition treaty with Sweden, so the expulsion was handled as an immigration violation by Cambodia, allowing it to act without a court hearing.

The Pirate Bay is one of the world's biggest free file-sharing websites, offering millions of users a forum for downloading music, movies and computer games.

Svartholm Warg and three Pirate Bay colleagues were sentenced in 2009 to one year in prison and ordered to pay 30 million kronor (NZ$5.6 million) to major entertainment companies, including Warner Bros, Sony Music Entertainment, EMI and Columbia Pictures, for copyright violations.

All four defendants denied the charges, arguing that The Pirate Bay doesn't actually host any copyright-protected material itself. Instead, it provides a forum for its users to download content through so-called torrent files. The technology allows users to transfer parts of a large file from several different users.

Svartholm Warg failed to appear at an appeal hearing in 2010. At the time, his defence attorney told the court he had received text messages from Svartholm Warg's mother saying her son had fallen ill in Cambodia and would not appear in court.

The appeals court reduced the prison sentences for the three other co-founders from one year to between four and 10 months and raised the amount they have to pay in damages to the entertainment industry to 46 million kronor.

Some in the international hacker community took offence at Svartholm Warg's detention by Cambodian authorities, saying he was being persecuted for alleged links to WikiLeaks and its founder Julian Assange.

A hacking group calling itself NullCrew claimed to have broken into several Cambodian websites last week in retaliation.