The prime ministers of Australia, Britain and New Zealand yesterday adopted President Carter's position on the 1980 Moscow Olympics by asking their national Olympic committees not to take part in the games.

There were signs from other major world capitals yesterday that other governments are leaning toward similar action.

In Japan, the ruling Liberal Democratic Party issued a statement saying the government should support a boycott of the Moscow Olympics. How ever, the party is fragmented and its statement will not bind the government of Masayoshi Ohira, which has reacted cautiously on the Olympic issue.

There were strong indications yesterday that the West German government realized that it would be under great pressure to follow the U.S. lead on the Olympics issue, though it has been noncommittal in public statements. Hans-Dietrich Genscher, the German foreign minister, has been in Washington for talks with Carter administration officials, who have pressed him hard on the need for western unity on the Olympics.

In all these countries, as in the United States, the national Olympic committees, not the governments, have the final say on whether to go to Moscow or seek to move the games. So far, no national Olympic committee of a major western nation has gone out in favor of a boycott or of a change of location.

The reactions of these nations were being watched closely in Peking, where the Chinese Olympic Committee said that if more than half of the countries in the world decide not to send athletes to Moscow, China will do the same.

The State Department denied suggestions in an article in yesterday's Washington Post that the Carter administration might postpone the Feb. 20 deadline it has set for the Soviets to withdraw from Afghanistan or face U.S. withdrawal from the Summer Olympics.

State Department spokesman Hodding Carter said the White House official quoted in the article was "off base."

At the White House, a senior aide to the president said, "We haven't made any change -- it's Feb. 20, period."

This senior official expressed satisfaction that many foreign governments are indicating support for Carter's initiative to move or postpone the Olympics to get them out of Moscow. Enough goverments seem ready to go along with the United States "to really make a difference," this source said.

State Department officials speculated privately yesterday that the Soviet decision to arrest and forcibly remove Soviet dissident leader Andrei Sakharov from Moscow might add new impetus to the movement to move or boycott the Moscow Olympics.

The United States is actively pursuing the possibility of moving the Olympics to another site. Officials involved said yesterday that Montreal looks like the best candidate. It still has all the necessary facilities, including complex television cables, these officials said, but not an Olympic Village, (Housing built for competitors at the Montreal Olympics of 1976 is now occupied by Canadian citizens.)

Carter administration officials said athletes could be housed in college dormitories, including some in the New England states and then be flown or driven into Montreal to compete.

One senior official noted that the U.S. Olympic team has been planning to base many of its athletes in West Berlin during the Moscow Olympics, flying them to the Soviet capitol only for their events.

However, a move to Montreal, or to multiple sites, as President Carter has suggested, would require the support of the International Olympic Committee, and the administration doubts that will be forthcoming. More likely, it seems, is a half-baked Moscow Olympics involving athletes from some countries and not from others.

The French Olympic committee, for example, announced yesterday that it had already accepted the formal invitation to take part in the Moscow Olympics. The invitation was received Monday.

Officials note that there are precedents both for boycotts of the games and for holding some of them in different countries in the same year. In 1956, the equestrian competition was held in Stockholm because the Australian government, main host for those Olympics, refused to let foreigners import their horses into Australia.

The Soviets refused to participate in any Olympics until 1952, apparently because they were afraid of being humiliated in competition with western athletes. In 1956, the Netherlands, Spain and Switzerland boycotted the Olympics to protest the Soviet invasion of Hungary.

The British prime minister, Margaret Thatcher, urged her country's Olympic committee to seek to move the games from Moscow this year, and she offered sites in Britain for some of the Olympic events. The British Olympic Committee is opposed to any move, or boycott, but it promised to consider Thatcher's request.

The Australian prime minister, Malcolm Fraser, wrote his country's Olympic Committee, recommending support of Carter's position. The Australian committee also has opposed any interference with the Moscow Olympics for political reasons.

Canada has already announced support for Carter's position.

In Washington yesterday the reconvening of Congress provided an occasion for an outpouring of rhetoric denouncing the Soviet invasion of Afghanistan and favoring action to move or boycott the olympics. Senate Majority Leader Robert C. Byrd (D-W.Va.) said "an overwhelming majority" of Senators would favor a boycott.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) said he hoped the House would approve a proboycott resolution by the end of the week.

Several such resolutions were introduced in the Senate.

A new national opinion poll conducted for the Associated Press and NBC News found that Americans favor Carter's Olympics position by 49 to 41 percent, with 10 percent undecided.