Even though they insist that "there is no substitute for the Olympic Games," and remain hopeful that a United States boycott of this summer's Moscow Olympics still can be averted, officials of the United States Olympic Committee (USOC) are going ahead with plans to provide makeshift national and international competitions if American athletes don't participate in Moscow.

The USOC plans have been developed independent of the "alternative games" the White House and State Department have been attempting to organize, but USOC Executive Director F. Don Miller says he will seek a meeting with administration officials, probably within the next two weeks, to explore the possibilities for merging the projects.

The USOC's preliminary plans call for both a "National Sports Festival" for U.S athletes only, probably at the same time as the Moscow Olympics July 19-Aug. 3, and an international competition in all 21 summer Olympic sports in one city, either in North America or Europe, some time between Aug. 15 and the first week in September.

Montreal London, Munich and West Berlin appear to be the cities receiving the most serious consideration for the international games.

Philadelphia, Indianapolis, Colorado Springs and a Tri-State alliance of cities in New York, New Jersey and Pennsylvania are the most likely candidates for the U.S. games, and might also be considered for the international meet.

The site for the USOC "contingency games" ultimately will be determined by the availability of sports facilities, accommodations, organizational manpower and funding.

The exact dates -- within limits imposed by the Olympics on one hand and the start of the 1980-81 academic year on the other -- will be determined primarily by the program schedule of U.S. television and the dates of international sports competitions already scheduled for the post-Olympic period.

The USOC Administrative Committee, at its meeting Saturday in Colorado Springs, gave Miller and his staff approval to continue developing plans for these competitions -- to be held if the USOC declines its invitation to Moscow because of the Soviet invasion of Afghanistan as the Carter administration has requested.

Miller said he probably will discuss the USOC plans at a meeting with representatives of about 15 national Olympic committees in Brussels on Saturday, and with the national governing bodies of the various summer Olympic sports at a meeting in Colorado Springs a week later.

Between those meetings, he hopes to consult with administration officials. White House counsel Lloyd Cutler and Nelson Ledsky, who heads the State Department's special Olympic Task Force, yesterday met with government officials of a dozen countries in Geneva and presented the concept of post-Olympic "alternative games" at several international sites, linked by satellite television.

Miller said there was no way the administration could organize a meaningful competition of this type without the support of the international amateur sports establishment. The International Olympic Committee (IOC) and its affiliated national Olympic committees and international sports federations might approve of a post-Olympic competition "if it was approached in the right way," he said.

"I don't think the IOC and the federations would disapprove as long as such games did not use Olympic terminology or any other limitations that would give the impression that they were competitive to the Olympic Games," Miller said.

"What we have in mind is a competition that would provide a meaningful experience for athletes deprived of the opportunity to compete in the Olympic Games in Moscow, but it would not be called 'alternative' or 'counter-Olympics." We find that terminology offensive. We believe there is no substitute for the Olympic Games, and we will not be involved with any competition that competes with or erodes the prestige of the Olympic Games," Miller said.

Miller said he thinks the administration believed initially that it could organize "alternative games" without the support of the IOC and its affiliated organizations, but that they now recognize completley that they can't.

Other USOC sources said they thought the administration had under-estimated the importance of getting approval from the international sports federations, overestimated the rights money U.S. television networks would be willing to pay for "alternative games" and failed to realize the complexity of organizing international sports competition.

Miller said he thought the administration, for a number of reasons, had so far "bypassed the USOC completely" in its attempts to organize "alternative games." Miller said it still would be possible for the parties to work together as long as the games in question "were not construced in any way as competitive to the Olympic Games."

Miller is expected to sound out influential officials of other national Olympic committees at Saturday's meeting in Brussels, and adjust the USOC's preliminary plans in accordance with their advice.

"Once we have out plans developed, I would say within the next two weeks, there would have to be a discussion to see how they mesh with the administration's plans in order to facilitate a program," Miller said. "Unless something is done in the relatively near future, we won't be able to accomplish anything, because it takes a lot of organizational and logistical support to put something like this together.

The USOC plans contain many options, including national competition only, international competition only, and both.

The USOC would prefer holding competition in all sports at one site, rather than the administration's plan for "clustering" four or five sports at each of four or five sites because "the interchange between athletes of various sports and the exchange of ideas is an important part of the experience and the total learning process," according to Miller.

Miller emphasized that the USOC is making contingency plans only. It has not abandoned hope that a Soviet withdrawal from Afghanistan, and consequent shift of U.S. public opinion in favor of participating in Moscow, might prompt President Carter to change his "irrevocalbe decision" on the Moscow Games.

The USOC has said it will comply with the president's request, but its administrative committee recommended Saturday that no formal response to the Moscow invitation be made until the May 24 deadline. That is in the event the president backs off his hard-line opposition.

Jody Powell, White House press secretary, said yesterday, when asked about the USOC's latest actions. "The president has made his decision, and it will not change. . . . They said they would abide by the president's decision, and I assume they mean what they say."

Miller said that if U.S. athletes do not go to Moscow and USOC plans for new competitions go into effect, he would try to finance them through television revenues and would seek a government subsidy.

"We have had discussions with the three American TV networks, and will have more in the upcoming weeks, but I doubt that the rights fees would cover the costs of such games," Miller said.

"I remain optimistic that there will be changes in the world situation that will permit us to go to the Moscow Games, but if not, I think a meaningful experience has to be provided our athletes. Since our government is the catalyst for the problem, I think they have some financial responsibility to assure that the meaningful experience is provided."