Conference in Europe aims at reducing East-West tensions

Even with East-West relations at their worst in years, preparations are getting under way for yet another set of disarmament negotiations. The first phase of this exercise will be aimed at reducing tensions in Europe by negotiating possible ''confidence-building and security-building measures.'' A second phase will eventually tackle nonnuclear disarmament in the region.

This week the 35 countries involved in the lengthy and frustrating European security conferences are gathering once again in Helskini. Their aim this time: to prepare for a new conference on disarmament in Europe. It is to get under way in January in Stockholm.

Representatives from both the Western alliance and the Warsaw Pact, including the United States, Canada, and the Soviet Union, as well as all small and neutral European countries, except isolated Albania, will be present in Helsinki. They will spend three weeks working on the agenda and timetable of the formal sessions in Stockholm. Like the European security conference itself, which has been working off and on for the past decade, this new effort is expected to last years.

The American representative at the talks, James Goodby, has been in Europe consulting with allies and some neutral countries. He told journalists here that ''the prospects are a little unpredictable.''

He explained that it could ''degenerate'' into vague propaganda exchanges or open up ''realistic and practical ways'' of improving security. The United States, which in the past was less enthusiastic than European participants about the concept of such an exercise, will insist on strict adherence to the mandate prepared for this conference during the recently concluded European Security Review conference in Madrid.

In Madrid, the US had argued for greater progress on human rights in the East before accepting a new conference on confidence-building and disarmament. West Germany and other European countries have been intent on keeping as many lines of communication and negotiations open with the East as possible.

The idea of a conference on disarmament in Europe was first launched by former French President Valery Giscard d'Estaing in 1978 at the United Nations special conference on disarmament.

''Confidence-building measures,'' which form the first priority on the Stockholm conference agenda, are also contained in the Helsinki Final Act on European Security and Cooperation, which was signed by the 35 countries in 1975. They include advance notification of military maneuvers in Europe involving more than 25,000 personnel and the invitation of observers from neighboring countries.

Many similar measures, such as exchanges of military observers and information, limitations on the number of troops participating in military exercises, and prior notification of any troop movements, have been discussed at other ongoing East-West negotiations.

Ambassador Goodby said the NATO allies ''were working on a whole package of measures'' to present at the meeting. He said the aim was to ''achieve greater clarity about the perception of military activity to make military activity more calculable.'' Participants in Helsinki talks Austria, Belgium, Britain, Bulgaria, Canada, Cyprus, Czechoslovakia, Denmark, West Germany, Finland, France, East Germany, Greece, Hungary, Iceland, Ireland, Italy, Leichtenstein, Luxembourg, Malta, Monaco, The Netherlands, Norway, Poland , Portugal, Romania, San Marino, Soviet Union, Spain, Sweden, Switzerland, Turkey, United States, Vatican City, Yugoslavia.