AMSTERDAM: A Dutch court on Wednesday ordered two major Internet service providers in the Netherlands to block their customers from accessing The Pirate Bay website or face large fines.

The Swedish-born website has been a thorn in the side of the entertainment industry for years by helping millions of people download copyrighted music, movies and computer games. In 2010, a Swedish appeals court upheld the copyright infringement convictions of three men behind the site, but it remains in operation.

The Dutch ISPs Ziggo and XS4ALL had resisted demands by a copyright holders' organization to block their subscribers' access to the site, arguing they should not have to act as censors.

But the Hague District Court said in its written ruling they must do so within 10 working days or face fines of (euro) 10,000 ($12,750) per day.

Another option, individually pursuing ''many thousands of subscribers in the Netherlands who trade files via The Pirate Bay would be, in the court's judgment, no less a far-reaching measure,'' the court said.

Past attempts by the copyright organization Stichting Brein had either failed or proved ineffective: Dutch courts have repeatedly found that downloading copyrighted files is not illegal.

Uploading them is illegal, since it is considered publishing without permission, but it can be difficult to prove a person has uploaded a file without using spying techniques that are themselves illegal.

In 2009, an Amsterdam court ordered The Pirate Bay itself to block traffic to the Netherlands, but that proved unenforceable since the site is hosted outside the country.

The Pirate Bay provides an index to BitTorrent files, which can be used for trading media such as movies, music and computer games. The site has more than 20 million users globally.

''The court considered it proven that 30 per cent of the subscribers of Ziggo and 4.5 per cent of the subscribers of XS4ALL have recently traded files via The Pirate Bay,'' the ruling Wednesday said.

''Because of the (reciprocal) nature of the so-called BitTorrent protocol that's used for this, the court assumes that subscribers didn't just download the files but also uploaded them and so infringed on copyrights,'' it said.

A Finnish court reached a similar verdict in a similar case against an ISP there Monday, though such rulings may still not mean the end of The Pirate Bay.

In November, the European Court of Human Rights found in a Belgian case that copyright organization demands for an ISP to monitor its customers' visits to The Pirate Bay and analyze file-trading traffic would be a violation of their privacy.

Ziggo and XS4ALL have not yet said whether they plan to appeal the ruling, but they are obliged by Dutch law to carry out the verdict while an appeal is under way.

Stichting Brein, which is funded by various copyright holder groups, said Wednesday it plans to bring similar complaints against other Dutch ISPs.