President Carter yesterday took a hard swing at the business community, accusing it of forming "selfish . . . special-interest groups" to spread "misinformation" about his proposed agency for consumer protection.

The bill creating the independent agency, intended to be an advocate for consumers within other government agencies, has run into trouble in Congress.

Its chances for passage are rated a toss-up by some supporters, who say business groups have gone to the point of compiling lists of congressional campaign contributors and asking those who gave to communicate their opposition to the recipients of their gifts.

"Now when it is sure that the White House will approve this legislation . . . the lobbyists have come out of the woodwork and the Congress is under intense pressure," Carter old a meeting of the agency's supporters.

"I think the action of those who oppose this legislation is ill-advised . . . Unfortunately, when business leaders organize and hire a staff and hire lobbyists, they lose that individual commitment to their customers and the lobbyists' only commitment is to their employers . . ."

The U.S. Chamber of Commerce, one of the groups leading the fight against the bill, promptly issued a statment saying a new agency would contradict Carter's promise to shrink the federal bureaucracy.

The President said he sees ". . . a separation here between what individual business leaders want and know is fair and what their spokesmen espouse on Capitol Hill.

"The proposal is for a tiny agency just to be a focal point for equity and fairness," he said. The Proposed $15 million first-year appropriation is less than the Defense Department or Health, Education and Welfare spend in an hour, he said.

After Carte spoke, some of the groups and individuals who for years have asked for a consumer protection agency announced formation of a Committee for the Consumer Protection Bill, to generate pressure at the congressional district level in favor of the legislation.

They ranged from the AFL-CIO to John Hechinger, owner of Hechinger's hardware chain in the Washington area.

Yesterday the President also visited the Organization of American States headquarters to sign the 1969 Inter-American Convention on Human Rights, which Presidents Nixon and Ford refused to endorse.

The convention, which spells out political and social rights and includes the right to freedom from slavery, has been signed by 12 of the 22 Latin American OAS members.

Although Carter referred to the convention as "a legally binding document," it needs Senate ratification to achieve that status in U.S. law. Only two countries, Costa Rica and Colombia, have ratified it, and nine more are needed for it to go into force.

Nations signing the agreement promise to provide freedom from arbitrary arrests and detention, to assure the rights of free speech and religions, and to end torture and the mistreatment of prioners.

The convention also sets up a court with board powers to consider complaints that any signatories have violated it.

Carter also attended a swearing-in ceremony for three scientists, in what he called "a re-cementing" of the relationship between science and politics.

They were psychiatris Peter Bourne, "one of the best personal friends I have in the world," as director of the Office of Drug Abuse; geo-physicist Frank Press as the President's scince adviser; and psychologist Richard Atkinson as director of the National Science Foundation.