ALGIERS, Algeria (AP) _ A national conference opened today to steer Algeria out of its bloody political crisis, but it risked becoming a sham because of a boycott by five of the six biggest parties.

Preparations for the conference were marred by debate about whether supporters of the banned Islamic Salvation Front - the main fundamentalist movement - should be allowed to participate.

In a surprise front-page report today, the government-run newspaper El Massaa said four representatives of the Islamic Salvation Front would attend. But conference chairman Youssef Khatib denied the report, and journalists covering the opening session did not see the delegates.

The government's two-year crackdown on fundamentalists has been at the root of escalating violence that has destabilized the country.

Though five of the biggest legal parties boycotted the two-day conference, delegates were sent by labor unions, professional groups and civic associations, as well as dozens of minor political parties. The conference is intended to establish a transitional government that would guide Algeria toward elections.

Algeria has been ruled for the past two years by the five-man High Committee of State, installed after the army canceled a second round of parliamentary elections that the Islamic Salvation Front was winning. The subsequent crackdown on fundamentalists triggered a violent backlash, and more than 2,000 people have been killed in two years of assassinations, bombings and security-force raids.

The government - its leaders fearful of assassination and unable to suppress the insurgency - has tried to establish indirect contacts with the fundamentalist movement. But Salvation Front leaders in exile have set tough conditions for opening a substantive dialogue.

The ruling council is scheduled to cede power Monday to a new president to be selected by the national conference. The president would oversee a transitional government that would set the stage for presidential and legislative elections in three years.

As the conference date approached, one after another of the main legal parties decided not to participate, including the National Liberation Front, Algeria's former ruling party.

Hocine Ait Ahmed, head of the Front for Socialists Forces, the first party to bow out, said the conference would be a ''sham.''

''We are going from an authoritarian transition to a more authoritarian transition,'' said Ait Ahmed, who lives in exile in Switzerland. He was quoted in an interview with the French daily Le Parisien Aujourd'hui.

Of the six non-fundamentalist parties that received more than 100,000 votes in the last elections, only the moderate Movement for an Islamic Society was represented at the conference.

The session was held at a heavily guarded seaside conference center 18 miles west of Algiers. The president of the ruling council, Ali Kafi, gave an opening speech, but most of the work was to be done in closed session.

Authorities have used harsh measures to try to contain the fundamentalist insurgency, including a state of emergency, curfews, special anti-terrorism courts and frequent sweeps by security forces. But assassinations continue, targeting judges, intellectuals, journalists and foreigners, 26 of whom have been killed since September.

Human rights officials say death squads have formed to retaliate for the killings, striking in areas known for fundamentalist sympathies.

Foreign executives, as well as government and military officials, move about under tight protection, and security forces watch over businesses, consulates and schools used by foreigners. The economy is in desperate condition and desertions from the army reportedly are increasing.