Thousands of police auxiliaries, who once helped in the fight against armed Islamist groups, tried on Monday to march on the capital to demand pay rises and other job benefits but were blocked by police, organisers said.

Around 40,000 men, according to the organisers, had reached Birkhadem outside the capital, Algiers, by early afternoon but hundreds of policemen prevented them from moving further, one of the marchers, Lahlou Aliouat said.

The protesters took off at 0300 GMT from the city of Blida, south of Algiers, and marched 48 kilometres (30 miles) under scorching heat.

"We want the same benefits as the troops and the security forces who are taking part in the struggle" against armed groups, Aliouat told AFP.

The auxiliaries, known in Algeria as "communal guards" were set up in 1994 to bolster local police in villages across the country where authorities were locked in a deadly confrontation with armed Islamist groups.

The auxiliary corps, which numbers 93,000 men, are demanding the same benefits as policemen and troops in Algeria.

Specifically they are asking for pay rises, round-the-clock health insurance to replace the current eight-hour coverage they get while on the job, and retirement after 15 years of active duty.

They also demand the option of joining the ranks of the police force or the gendarmerie, a French-styled paramilitary police unit.

In March 2011, some 10,000 communal guards flooded the streets of Algiers, with similar demands, in defiance of a ban on demonstrations. Interior Minister Daho Ould Kablia received a delegation.

"Our objective is to reach the president's headquarters," Aliouat said on Monday.