A Saudi political reform activist said on Thursday the authorities had blocked his Internet forum as part of a wider crackdown on freedom of expression in Saudi Arabia.

"I want to put government bodies and public opinion in our country before the facts of how certain elements are infringing human rights," Ali al-Dumaini said in a statement published on blog sites.

Dumaini, who was jailed in 2005 along with two other activists for campaigning for political reforms, said his "Dialogue and Creativity" forum had discussed issues of human rights, tolerance and democracy.

He said the block by telecommunications authorities, who filter out many sites, was part of a series of measures to stifle liberal voices.

Activists say the Interior Ministry, run by the hawkish Prince Nayef Abdul-Aziz, has closed several weekly "salons" in recent months where Saudis gathered to discuss political and social issues.

Ten men were arrested in February on suspicion of "funding terror" but their supporters say some of them were planning to set up a political party.

"We hope these are passing incidents that we will get over in light of our optimism about the path of reform established by King Abdullah," Dumaini said.

Saudi Arabia is an Islamic state dominated by the Saudi royal family with no elected parliament and no political parties. A close ally of the United States, it is also the world's biggest oil exporter.

King Abdullah is seen as a supporter of cautious reform but diplomats say other senior royals close to the powerful religious establishment have hindered his plans.

The semi-official al-Riyadh newspaper said on Thursday the official National Society for Human Rights had asked the telecommunications authority to unblock Dumaini's site.