The Executive Board of the International Olympic Committee (IOC) will consider next week proposals for deemphasizing nationalism at the Olympic games, including possible cancellatin of opening and closing ceremonies at this summer's Moscow Games.

However, the IOC presently has no plans to reconsider postponement or cancellation of the July 19-Aug. 3 Games because of the continued Soviet military presence in Afghanistan, which may be the basis of many nations staying away.

The nine-man Executive Board which includes one Soviet member, will meet April 21-23 at IOC headquarters in Lausanne, Switzerland. High on the agenda is a review of the Moscow Games, which could be boycotted by a substantial number of major nations following the U.S. Olympic Committee's decision last weekend not to send a team.

President Carter's call for a widespread boycott appears to be gaining momentum in the wake of the USO's decision. Japan, West Germany and Canada now seem almost certain to follow the U.S. lead, while Great Britain and Australia are among the countries whose governments are putting renewed pressure on their athletes to bypass Moscow.

Representatives of 16 Western European national Olympic committees, who met in Brussels last month to discuss "the Moscow problem," will propose plans aimed at protesting Soviet aggression without precluding athletes from participating in the Moscow Games.

Among the options to be presented will be canceling the elaborate opening and closing ceremonies planned by Moscow Olympic Organizing Committee. This theoretcally would be a painful slap at the Soviets, who place great stock in nationalistic pomp and ceremony.

Some national Olympic committees also are considering not having their athletes participate in any ceremonies, including medal presentations, and keeping them outside the Soviet Union except for the time necessary to compete in their events. These means of protesting Soviet aggression also were proposed by U.S. athletes as an alternative to the decision the USOC made last weekend not to enter a team.

The Carter administration has rejected such proposals as ineffective and insufficient for punishing the Soviet military intervention in Afghanistan, and has informed the governments of other nations of its position.

Expected to receive favorable attention at the IOC meetings are proposals, supported by the Western European delegation, that athletes in all future Olympics march in ceremonies grouped together by sport, rather than by country. Proposals also will be offered to limit the use of national flags and anthems, substituting instead flags of the IOC or national Olympic committees.

The Executive Board also has agreed to separate meetings with delegations from the Olympic committees of the United States and Kenya. USOC Executive Director F. Don Miller and President Robert J. Kane will head the U.S. delegation.

Miller said yesterday he thought it was "possible" that the IOC would go as far as canceling opening and closing ceremonies. "I think it will be discussed. How it will come out, I don't know. I wouldn't want to speculate on it," he said.

The possibility of changing IOC rules to permit athletes to enter the Games as individuals, rather than as representatives of their national Olympic committees, will also be raised. Miller said it is "highly unlikely" that such a rules change would be given favorable consideration because it is strongly opposed to most committees, including the Western European coalition and the United States.

Miller said he knows of no plans for the IOC to reconsider cancellation or postponement of the Moscow Games, even though IOC President Lord Killanin of Ireland left open that possibility on Feb. 12, when the IOC rejected a USOC proposal to that effect at its session preceding the Winter Olympics in Lake Placid, N.Y.

"I feel from my discussions with Lord Killanin that he has constantly discussed the problem with the Moscow Olympic Organizing Committee. I think he will report on these discussions at next week's meeting, so a lot depends on what has or has not been accomplished in their "view," Miller said. d

He said that the IOC continues to insist that there has been no abrogation of the contract it has with the Moscow organizers, and therefore no legal basis for postponing or canceling the Games.

The USOC will not again push for stripping Moscow of the Games, as it did in Lake Placid IOC meetings, because it does not want to do anything to jeopardize Los Angeles as the host of the 1984 Summer Games, Miller said.

"I don't want this to impact on L.A. We are a party to that contract. There are some people in the IOC who might try to indicate that we have let politics intrude on our decision making, in violation of IOC rules, in deciding not to send a team to Moscow, and that we should therefore be expelled or not allowed to host the Los Angeles Games," Miller said.

Vitaly Smirnov, vice president of the Moscow Organizing Committee, and a member of the IOC Executive Board, raised the possibility of sanctions in a Moscow press conference yesterday where he denounced the USOC's boycott decision.

"Following this, it is possible that the 1984 Olympics will not take place in Los Angeles. This could be one possbile consequence of this crude and unprecedented interference in the Olympic movement," Smirnov said.

Miller and Kane have said repeatedly that the USOC made its decision through proper channels, according to its constitution, and did not violate Olympic rules. Killanin and IOC Director Monique Berlioux were kept fully informed, and are understood to agree that the USOC is not subject to any sanctions.

During next week's meetings, the IOC will also meet with the 26 international federations that govern the Olympic sports. Miller predicted that they "will take a unified position that the Games will go on in Moscow as scheduled, and a unified, firm position against any pre- or post-Olympic competitions that might be considered competitive to the Olympic Games.

Miller said that, in his judgment, the concept of "alternative games" -- any international sports festival involving all sports at one site or clustered in four or five sites to give a world class competitive opportunity to athletes barred from going to Moscow -- is "dead."

"A lot of different things could manifest themselves as a result of these meetings in Europe next week, so we have to maintain a degree of flexibility," said Miller. "But right now, from what I can detect on a worldwide basis, there is a rejection of so-called alternative games in any form. This has been rejected by our (USOC) executive board, the athletes, the European Olympic committees, and the U.S. national governing bodies (of the Olympic sports)."