The leaders of Turkey and Greece agreed yesterday to meet in March to try to settle differences between their own countries that have soured relations between them and the United States and weakened the southeast flank of NATO.

It will be the first meeting of Turkish and Greek premiers since 1967. That two-day meeting was a fiasco, leading to a Turkish threat to invade Cyprus which was only averted through U.S. mediation.

In 1974, the Turks did invade Cyprus following an Athens-backed coup on the island aimed at uniting it with Greece. The two NATO allies came close to war. Greece pulled its forces out of the alliance, charging that the United States had failed to keep the Turks in check. The U.S. Congress then slapped an arms embargo on Turkey and Ankara retaliated by closing American bases here.

The Cyprus conflict spawed other Turkish-Greek disputes, including rival claims to the Aegean seabed, where oil was discovered in 1973, control of Aegean air space and fortification of Aegean islands.

Diplomats do not expect immediate disentanglement of this morass but are hopeful the March summit will be a start.

The initiative for the meeting comes from Turkish Premier Bulent Ecevit. Ecevit, who is also a poet, wrote of Greeks and Turks in 1949: "a love lies hidden in our hearts/for days of peace". The day after taking office in january, he proposed a meeting with Greek Premier Constanine Karamanlis.

Karamanlis stalled on the ground that peace hopes might be dashed because of inadequate preparations.

Ecevit, who has pledged to give top priority to solving the Cryrus conflict and other disputes with Greece, tried again earlier this week, proposing "initial talks" with no rigid agenda to prepare for "concrete solutions through the negotiating process."

On this basis, Karamanlis agreed to meet Ecevit next month, saying it was "the duty of two governments to leave no avenue unexplored." A date and place for the summit meeting is to be fixed through diplomatic channels, according an exchange of letters made public in Ankara and Athens yesterday.

Discussions at lower leves have already been set on the problems of Aegean seabed and air space rights, and peace talks between the Greeks and Turkish communities on Cyprus have been revived since Ecevit returned to power.

It is hoped here that the summit will create the necessary political will to ensure that these talks proceed smoothly.

Special correspondent Mary Anne Weaver reported from Athens:

Greek government sources cautioned that the summit meeting ould be strictly "exploratory" and that no substantive negotiations were scheduled to take place.

According to qualified sources, the meeting will be at a location "where there ill be no public disturbances, where privacy can be secured," presumably eliminating both Athens and Ankara as potential sites.

Karamanlis's agreement reversed his decision last month that any summit meeting must have "adequate preparations" rather than risking failure through haste.

But Ecevit, in a letter delivered to Karamanlis on Wednesday referred to his desire for "initial talks," not aimed at finding "concrete solutions to specific issues" dividing the quarreling states.

Secretary of State Cyrus Vance is credited in some diplomatic circles with having played a role in finding mutually acceptable ground on which the taciturn Karamanlis and the flamboyant Ecevit could meet.

"By his change of language and emphasis," said one diplomatic official, "Ecevit has allayed Greek fears that if the talks were approached on the basis of negotiations, there would be the outlines of a comprehensive settlement, or package deal."

Greece has consistenly refused to become involved in the Cyprus Problem, believing that it is a matter to be negotiated by the Greek and Turkish communities of that beleaguered island state.

"The emphasis of the karamanlis-Ecevit meeting will not be Cyprus, but Greek-Turkish relations," an official source reiterated.