Four leading Hungarian intellectuals who have been critical of the Communist "system" in their country have been quietly pressured into leaving their homeland for the West.

The action marks the first known occasion in recent years that the Communist government of Janos Kadar has used the technique of encouraging emigration to get rid of its dissidents and critics.

The use of forced exile has been widespread in Eastern Europe, especially in East Germany and to a lesser extent in the Soviet Union, Czechoslovakia and Poland, as internal criticism has grown in the aftermath of the 35-nation Helsinki accords on European cooperation and human rights.

Hungary, however, has traditionally been viewed as the least repressives of the Soviet-bloc countries. Early in 1977, when a group of 34 Hungarian intellectuals signed a protest against Czechoslovak harassment of civil rights campaigners, many experts emphasized that Hungary had not taken action against the signers.

In September, however, The Washington Post reported from Budapest that three or four critics were being pressured to leave.

At the time, sources said that the government was delaying their departure because an East European dissident's art exhibition was being held in Venice later in the year and Hungarian leaders did not want their dissidents showing up there as recent political exiles.

Now, however, four dissidents have left Hungary, according to an interview with them and Hungarian Culture Minister Imre Pozsgay in L'Unita, the Italian Communist Party newspaper.

The four - philosopher Agnes Heller and her husband, Ferenc Feher, and philosopher Gyorgy Markus and his wife, sociologist Maria Markus - were among the 34 who signed the protest last year and who also protested the 1968 Soviet-led invasion of Czechoslovakaia.

The Markuses are reported to be in West Berlin and Heller and her bhusband have accepted three-year fellowships in Australia, where Ivan Szelenyi, a former prominent Hungarian dissident and sociologist, is teaching.

Heller, a marxist philosopher, is the most prominent of the four who recently left and was the intellectual leader of the dissidents in Budapest.

In the interview with the Italian newspaper, Pozsgay acknowledged the departure of the four scholars and called it a loss to Hungarian cultural life. But he said there had been a grave conflict with them over their objectives and although the government did not seek any drastic solutions, the arguments of the four could not be accepted and thus had to be stopped.

He left open the possibility that they might someday return but said that their work had to be banned because it opposed the political and ideological foundations of socialism.

Heller told the Italian paper that the four had been banned from publishing and had lost their jobs.

Nevertheless, she said, she was criticizing the system rather than the present leaders of Hungary and she offered some compliment to the Kadar government for going almost to the limit of what was possible within a Communist system strsuctured like the present one.

Relations between Hungary and the United States have been improving steadily lately as the Carter administration seeks better relations with individual countries of the Soviet bloc.

InJanurary, the United States returned the revered crown of Saint Stephen "to the Hungarian people" and yesterday it was announced in Washington that the two nations had concluded an agreement which, if approved by Congress, would give Hungary most-favored-nation status in trade relations with the United States, something the Budapest government has sought for many years.