In a major breakthrough on the Cyprus deadlock, Archbishop Makrios, president of Cyprus, met here today - for the first time in nearly 15 years - with the Turkish Cpyriot leader, Rauf Denktash.

The two men appeared to make concessions that opened the way to a resumption of the stalled negotations on a settlement.

The suprise meeting between the two antagonists, who have refused to recognize each other's title since the pro-Athens coup and subsequent Turkish invasion in 1974, required a significant formal concession from Makarios, since the meeting was held on a basis of equal ranking.

On the other hand, the Turkish Cypriot leader apparently was more conciliatory on territory, offering to reduce the Turkish occupation to less than a third of the island, with a hint of further withdrawals, according to a Greek Cypriot television account of remarks by Makarios.

Turkish Cpyriots, who are 20 per cent of the population, hold 40 per cent of the territory.

Denktash said that the issues of Greek Cypriot refugees' return, freedom of movement between the two zones and the right of settlement for Greek Cypriots throughout the island were all negotiable, the television report said.

These key Greek Cypriot concerns were mentioned in a letter that was the basis of the meeting.

By agreeing to meet his former vice president in this manner, Makarios tacitly recognized the stronger political position of the Turkish Cypriots, who demand a federate formula for Cyprus with a weakened central government and presidency.

At the same time the Turkish Cypriot offers on refugees and on territory, which would mean reduction of 6 per cent in territory they control, Turkish invasion divided this island in 1974.

Concern over Cyprus in Washington and in Europe has been growing recently and has reached here, Greece and Turkey.

The advent of the Carter administration, which has put Cyprus high on its list of foreign policy priorities, aroused expectations of a "now-or-never" bid to solve the dilemma. Both sides have been noticeably positioning themselves to convince Washington, Western Europe and the United Nations of their good intentions. Today's results.

"The meaning of today's event was to test whether the Cyprus problem could be discussed in a sincere atmosphere, and it has been a succesful exercise," Denktash told reporters.

Today's meeting appeared to clear away procedural obstacles to resuming the stalled talks. Makarios and Denktash apparently have set themselves up as sponsors of the negotiation to whom the negotiators can appeal if the bargaining bogs down.

The revival of active negotations gives new urgency to the fact-finding mission of U.S diplomats expected here and in Athens and Ankara soon. Both capials clearly gave their blessing to this latest initiative.

The discussions proceeded "without recriminations," a U.N. source repoted Makarios told Greek Cypriot correspondents afterward that he had told Denktash that he could not recognize Denktash's title as "president" and said that Denktash countered, "That's all right, I don't recognize your title of president either."

The only other person present during the nearly three hours of talks - in English - was the U.N. secretary general's special representative of Cyprus, Perez de Cuellar, the Peruvian diplomat who made the arrangements for the meeting.

After two weeks of secret preparations, the meeting was arranged in the U.N. headquartrs in No-man's-land near Nicosia's abandoned international airport. To reach this neutral spot, the two men approached the demilitarized zone from opposite sides in cars. Escorted by U.N. officers in berets, they finally sat down together in a former popular restaurant that is now part of the U.N. offices.

A further meeting between Makarios and Denktash is expected before talks begin between the two sides' permanent negotiators, who reached a stalemate last spring.

U.N. Secretary General Kurt Waldheim, who is to visit the Middle East next month, will add Cyprus to his itinerary, probably to chair this second meeting, Makarios said.