Yugoslavia has launched a drive against domestic dissent with tough police warnings delivered recently to several prominent dissidents, including the country's former vice president, Milovan Djilas, and a tightening in official controls over press and radio.

So far, however, the campaign has been kept within strict limits and while denunciations and self-criticism have become commonplace, no one has been arrested or purged. Western diplomats caution against reading too much into the crackdown, interpreting it as just more stage in the zig-zag course pursued by President Tito since he came to power in Yugoslavia after World War II.

The relatively harsh new political climate in Yugoslavia is not necessarily connected with Tito's current attempts to mend fences with Moscow, but will inevitably be welcomed by the Soviet leadership as a step in the right direction.

Djilas said that his recent criticisms of Soviet expansionism in newspaper interviews was one of the points taken up with him when he was summoned to a meeting with Yugoslav police last week.

Warning that "the most energetic measures" would be taken against him and his friends if he persisted in his activities, a plainclothes policeman said attack on foreign countries weakened Yugoslavia's position and were also punishable.

According to Djilas, he was also accused of attempting to form a subversive organization. The policeman described the five-minute interview as "a final warning," Djilas said.

It was the first time that Djilas has been called to see the police since 1972 at the height of a previous campaign against liberalism and nationalism.

Djilas, 67, who now lives quietly in Belgrade writing his memoirs and occasionally meeting foreign visitors, served nine years in prison after breaking with Tito in 1954 when he advocated more liberal policies.

Several other dissidents with whom Djilas has been in touch, including the Serbian writer Dragoljub Ignjatovic, have had their homes searched or been briefly detained by police over the last few weeks. Police questioned them on their contacts with nationalists from the northwestern republic of Croatia.

Yugoslav officials are very sensitive about any sign of organization between the country's ideologically diverse bands of dissidents. Recent contacts between dissident intellectuals from Serbia and Croatia, the two main ethnic groups in Yugoslavia have been condemned officially as attempts by enemies of the state to draft a common political platform.

A senior Croatian Communist official, Jure Bilic accused the dissidents of organizing a joint Serb-Croat front in preparation for some sort of "D-Day" an apparent reference to Tito's death. Tito will be 87 next month.