Television manufacturers and unions were critical of a United States agreement with Japan under which that country agrees to limit to 1.75 million the number of completed and unassembled color televisions it will ship to this country each year.

A coalition of manufacturers and unions, the Committee to Preserve-American Color Television (COMPACT), said that not only does the agreement set a level that is too high, it also does not become effective until July 1. In the remaining month and a half, industry and union officals said Japan could ship large numbers of television sets to the United States.

Washington Post special correspondent Andrew Horvat reported from Tokyo yesterday that Japanese manufacturers plan to export almost every thing they have in stock before June 30.

A source close to the Japanese electronics industry told The Washington Post, "Japanese manufacturers hope to build up stocks and keep their U.S.-bound exports, for 1977, well above the 2 million mark." The United States imported between 1.3 million and 1.5 million color sets a year in the early 1970s, with most of them coming from Japan, the Commerce Department reports. Color television imports fell-to 1.2 million in 1975 during the recession, then jumped to 2.8 million in 1976.

Television imports have been surging in 1977, government officials say.

Unions and companies pressed the International Trade Commission, set up to administer the 1974 trade laws, for relief and last March the commission ruled that the American television industry was being hurt by imports. It recommended that tariffs is increased to 25 per cent on televisions.

President Carter, worried about the potential of starting a string of protectionist moves around the gidbe, decided instead to try to negotiate a voluntary quota with Japan. Details of that tentative agreement - which the government is expected to announce Friday - were reported in The Washington Post and other newspapers Wednesday.

That agreement, restricts Japan to shipping no more than 1.56 million completed color sets and 190,000 substantially uncompleted, or sub-assembled, sets. It also encourages Japanese manufacturers to set up plants in the United States and exempts a set from the quota if about half the labor required to build it comes from the United States.

Jacob Clayman, of the AFL-CIO, and Allen W. Dawson, executive vice-president of Corning Glass Works, co-chairmen of COMPACT, said in a statement, "We find little cause to rejoice in a three-year agreement which permits imports of color television sets from Japan to rise by almost 60 per cent from the level which prevailed prior to the flood of imports which arrived in 1976."

Clayman and Dawson said they would have preferred a quota of 1.3 million sets that would apply to all countries rather than a 1.75 million restraint on Japan alone.

Fifteen unions and companies are members of COMPACT. Two major television manufacturers - GTE Sylvania, Inc, and Zenith Radio Corp - are not members of the coalition.

Special correspondent Horvat reported from Tokyo that between Jan. 1 and the time the agreement takes effect on July 1, 1.28 million Japanese sets will have reached the United States. That is more than Japan shipped to this country in all of 1975.

Sources in Japan's Ministry of International Trade and Industry said that major manufacturers will not be hurt by the quota - already Sony, Panasonic and Sanyo have set up facilities in the United States - but smaller Japanese makers will be hurt.