BELGRADE, Yugoslavia (AP) _ A witness at the trial of six men charged with anti-state activity testified Thursday that the defendants' meetings were mostly political in nature.

However the witness, Slavko Colic, said he could recall clearly only one lecture, given by defendant Milan Nikolic on the role of multinational corporations. Colic said that lecture was not politically biased.

Colic, a theater arts student who described himself as apolitical, was the first witness to testify that the private gatherings of the defendants were political. Others witnesses have disagreed with the prosecution's charge that the periodic lectures were politicial.

The defendants insist the meetings were primarily discussions of scientific and social questions and were not intended to criticize the Communist Party or government figures.

Police raided an apartment in April during one of the meetings and arrested the defendants. Besides Nikolic, 37, a U.S.-educated sociologist, they include journalist Dragomir Olujic, 35; Vladimir Mijanovic, 38, a sociologist; Miodrag Milic, 55, a writer; Gordan Jovanovic, 23, a student; and Pavlusko Imsirovic, 35, a translator.

They are charged with hostile conspiracy and counterrevolutionary activity, and face prison sentences of five to 15 years if convicted. The trial began in November, and diplomats see it as a test of freedom of expression and association in Yugoslavia, one of the most liberal Communist countries. Authorities in recent months have increased pressure on dissidents.

Colic said he stopped attending the meetings because the lectures were generally political. He testified that money was collected at the meetings for people who were in trouble with the government for their political persuasions.

In his original deposition Colic said the gatherings ''appeared to me to be illegal.'' However, he said Thursday he wanted to change that description to ''selective,'' meaning not open to everyone.

Pro-Western ideas came up at the lectures, he said. Some of the participants said the Communist Party should share power with trade unions, and there was talk of political dissidents being killed in set-up traffic accidents.

Meanwhile, intellectuals from Serbia, one of the six Yugoslav republics, reportedly used a regional conference to criticize the nation's legal system and restrictions on freedom of speech.

The state-supervised newspaper Politika quoted prominent theater critic Jovica Acin as saying at the conference, titled ''Literary Creativity and Cultural Policy Today,'' that the courts and police decide the country's cultural policy.

The newspaper Novosti quoted Zagorka Pesic-Goubovic, a former university professor who was dismissed in the mid-1970s for her political views, as saying, ''impartiality of the courts has long been shaken.''

It said she criticized the trial of the six men and called for an independent judiciary.