Chile's principal labor leaders tonight called a national general strike, accusing the government of Gen. Augusto Pinochet of repression and citing economic paralysis and a lack of basic freedoms. They said the walkout would last until the government "fundamentally changes its attitude."

The strike, set to begin Thursday morning, was called by a coalition of five labor confederations and Chile's key transportation union. It is the first such action attempted in a decade of military rule and the most severe challenge ever made to the government of Pinochet.

"We have resolved . . . what all Chileans desire--to fight for the restoration in our country of the institution of democracy, for the recovery of our freedom and rights. We are going to go together to the battle to give Chile back the prestige that has been taken away," said Eduardo Rios, one of the principal leaders of the group.

The strike was called six days after a massive and violent demonstration in Chilean cities against military rule and was precipitated by strikes in copper mines that began last Thursday. Sources said the action had been backed and would be coordinated in part by Chilean opposition political parties after intensive meetings during the weekend and today.

There was no immediate reaction to the strike call from the military government, which has sought during the past several days to isolate and neutralize militant labor leaders while offering conciliation to rank-and-file workers, middle-class sectors and the political right.

Earlier today, the Interior Ministry issued a statement calling on the public and the news media to "strictly respect" the suspension of political activity in effect in the country to help "national reconciliation." Tonight, Chilean journalists issued a statement saying the national media had been told by the government not to report protests, calls for strike or any other political move, including interviews with opposition leaders.

It was not clear how strictly the government intended to enforce the new censorship guidelines, but Chilean journalists said it was possible that they would be unable to broadcast or print the call for the general strike.

The opposition labor leaders also appeared to face a formidable task of organization in seeking a national shutdown. Although the labor leaders supporting the strike declaration nominally represent more than 70 percent of Chilean union members, only a minority--estimated between 10 and 30 percent--of Chilean workers belong to unions.

Three of the five union confederations in the National Command of Workers, which has led the recent national protest movement, are ad hoc organizations without legal ties to local unions, although they include many prestigious labor leaders.

The principal sectors expected to support a work stoppage are bus and taxi drivers, truck drivers and workers in construction, textiles, oil production and mining.

Chilean universities and organizations of professionals such as lawyers also are expected to back the action.

The agreement on a national strike by union leaders came after five days of intense discussion and internal struggle over whether the strike by copper workers in three of Chile's four state-operated mining centers could or should be expanded.

The final decision was taken as the government continued to arrest copper union leaders, replaced workers fired for striking and pressed criminal court cases against the 11 top leaders of the 23,000-member Copper Workers Confederation.

By tonight, a Santiago judge had ordered four top union leaders jailed in addition to Rodolfo Seguel, the copper workers union president and national protest leader whose arrest and court-ordered detention last Wednesday provoked the copper strike.

Today, some copper unions remained on strike in El Teniente and El Salvador mines, while other unions had returned to work while awaiting the outcome of the national union meeting and talks with government officials about the rehiring of workers.

The state-owned copper company, Codelco, which on Saturday announced the firing of 1,800 workers who participated in stoppages at El Teniente, El Salvador and La Andina mines, said today it was considering rehiring those workers who had "good backgrounds." Local copper union leaders said company officials had promised to rehire the majority of workers if unions returned to the job.

Two copper mines, El Salvador and Chuquicamata, the largest Chilean mine, remained under military control today, and a meeting by workers at Chuquicamata to decide on a strike was prohibited by military authorities.

A statement by Codelco said that copper production, Chile's primary source of export earnings, had dropped 6 percent in the past week because of the strike.

A number of labor and political leaders were reluctant to support the copper strike because they believed neither their unions nor the Chilean opposition were yet in a position to launch a full-scale confrontation with the Pinochet government.

However, their resistance was overcome by pressure from regional and local labor leaders and fears by copper union leaders that their organization would be destroyed if they were not supported by other unions.

The statement issued by labor leaders tonight cited repression by the government against last week's national day of protest, that resulted in five deaths and 1,350 arrests, and the "economic, social and political disaster which the economic and political model imposed on the country has led us to."

It also criticized "the illegal and arbitrary detention" of labor leaders and the firings of workers, which it said were "actions meant to destroy the national labor movement."

The document also mentioned the lack of "intellectual liberty," and said there was "a manifest governmental incapacity to attend to the legitimate and undelayable solution that the country urgently needs."