Thousands of riot police in riot gear have stopped government opponents from staging a protest march in the capital of Algeria.

Small groups of demonstrators angry at President Abdelaziz Bouteflika gathered in May 1 Square in the centre of Algiers shouting "Bouteflika out!". They waved newspaper front pages reporting Friday's overthrow of Egypt's President Hosni Mubarak.

But riot police hemmed them in, stopping them from carrying out a plan to march through the city. Other protesters trying to reach the square found their way blocked and at least one of the protest organisers was arrested.

After about three hours, hundreds of people left the square quietly, with police opening up gaps in their cordon to let them through. Some 200 young men from a poor neighbourhood nearby stayed on the square. Some threw objects at police.

Mubarak's resignation and last month's overthrow of Tunisia's leader have electrified the Arab world and led many to ask which state could be next in a region where an explosive mix of authoritarian rule and popular anger is the norm.

Many analysts say a revolt in Algeria is unlikely because the government can use its energy wealth to resolve most grievances.

Officials had banned Saturday's protest, citing public order concerns. A massive police operation, which started on Friday afternoon, appeared to have stifled it.

"I am sorry to say the government has deployed a huge force to prevent a peaceful march. This is not good for Algeria's image," said Mustafa Bouchachi, a leader of the League for Human Rights which helped organise the protest.