The West moved quickly today to try to guarantee that debate on the explosive issue of human rights would not be limited or diverted by Communist-bloc tactics as the 35-nation review conference on European security and cooperation opened here.

Acting on behalf of members of the European Common Market and backed by the United States, British officials proposed an agenda for the main part of the conference to begin in the fall that basically allows open-ended debate on all subjects. The agenda would also break with precedent and allow a number of open sessions.

The nearly 200 delegates who gathered here today are taking part in a perparatory session, expected to last some six weeks. They will try to lay the groundwork for the main conference, which is supposed to examine how well the 35 signers of the 1975 Helsinki agreement have implemented its provisions on military security, economic cooperation and human rights.

The opening cermonies in a new $30 million concrete-and-glass conference center here were very brief and, in fact, were overshadowed - temporarily at least - by events going on elsewhere in the Yugoslav capital.

In a hotel not far from the meeting plainclothes Yugoslav security police detained about 15 women from several Western European countries and the United States who were planning a demonstration at the conference site on behalf of Soviet Jewry. The women, from the London-based Committee of 35, were ordered out of the country and escorted to the airport by Belgrade police.

A Danish radio reporter who protested the detention of the women was also ordered out.

Later in the day, Yugoslav officials made it known that they had granted amnesty to 91 prisoners in Yugoslav jails. None of the 502 so-called "political prisoners" that authorities acknowledge are in jail here appeared to be among the 91, however.

The incident in New York yesterday in which a band of Croation gunmen shot their way into the Yugoslav mission to the United Nations also was reflected in the meeting here when Milos Minic, Yugoslav federal secretary for foreign affairs, added a paragraph to his welcoming speech about "sinister forces" that oppose detente and resort to propaganda and terrorism to undermine it.

Finally, there was also an undercurrent of concern in the U.S. delegation and among some Western Europeans here about the detention in Moscow of Los Angeles Times correspondent Robert C. Toth just as the Belgrade conference was getting under way.

One source speculated that the move may be part of a two-track Soviet policy of behaving property at Belgrade but making trouble for the United States that could provoke a stern White House attack.

That, in turn could unsettle Western European allies, who are afraid a new outburst might cause collapse of the conference and cause a spilt in Western cohesion here.

The Western plan for organizing the main Helsinki review meeting is a as follows:

The conference would start in late September or early October, a point on which little dispute is expected.

A "reasonable" duration for the meeting is 12 weeks, although actual closing date should be dictated.

Although British officials said today that on the basis of earlier discussions, many of the ideas in the proposed organization would be acceptable to the East, this is probably not one of them. The Soviet, especially, are likely to press for a short meeting with a definite close so that there is less time to linger on human rights.

The agenda would include "a thorough exchange of views on implementation" of all three portions of the Helsinki agreement - human rights, military security, and economic and cultural co-operation - plus discussions of way to deepen East-West relations and detente and establishment of the next reivew meeting.

The West envisions an initial series of open plenary meetings that would last about one week. This would be followed by perhaps three weeks of closed plenary sessions to discuss how the Helsinki accord has been implemented in the two years since they were signed.

Then would come work in smaller committees for discussion of implementation in greater detail. This is another thing the Soviets are almost certain to either reject or try to water down into a minimum of committee sessions.

This would be followed by further closed plenary sessions to try to work out a document summarizing the conference's work and conclusions.

The problem here is that the conference will operate on the basis of consensus, which means that a final document - presumably including any criticism - would have to be agreed on by all parties. Finally, the meeting would end with an open plenary session.