President Carter unveiled consumer affairs programs yesterday at 35 agencies that are designed to give the public a voice in decision-making and centralize these responsibilities with one official at each agency.

The plans were developed in response to an executive order that Carter issued last September.

Flanked by three Cabinet members, Carter praised the efforts to implement the order during a presentation to federal and private consumer-group leaders, many of whom have been frequent administration critics.

But reaction from consumer-group leaders who attended the White House briefing was mixed, with some praising the Carter effort and others expressing skepticism about its ultimate effectiveness.

"This shows how far we have not come in the consumer movement," said Ellen Haas, director of the consumer division of the Community Nutrition Institute. "It shows the lack of consumer clout in Congress and the administration's failure to put forth an effective legislative effort."

Haas said that the failure of Congress, despite Carter support, to pass legislation to set up a consumer representation agency, leaves consumers "with a federal agency program that is very muddied."

Another consumer activist, who asked not to be identified, said he couldn't bring himself to applaud Carter's entrance into the briefing room. "I spent the weekend bad-mouthing" Carter, the lobbying group official said. "I find it very difficult to be happy about this."

But Stephen Brobeck, executive director of the Consumer Federation of America, said the announcement "was what we could retrieve from the agency" defeat and said it was "quite nice" to come to the White House "and have something positive to talk about.

"This is a clear indication that the president considers consumer representation a high priority," Brobeck said, noting that as Carter appoints future agency consumer advocates, it would become important to consult consumer groups about the personnel developments.

Carter called the announcement "an historic development in our government" and took the occasion to chide "highly paid and competent lobbyists" who represent the interests that helped defeat the consumer agency legislation earlier in his term.

"When we protect consumers, we protect ourselves," Carter said. "I want the federal government to think like a consumer would think."

Appearing with Carter were Treasury Secretary G. William Miller, Agriculture Secretary Bob Bergland and Attorney General Benjamin Civiletti. Miller also praised the consumer program and said his department is "committed to establishing professional consumer affairs representatives in all Treasury bureaus and offices."

Esther Peterson, Carter's consumer affairs adviser and the primary administration coordinator of the project, said the agency representatives aren't problem-solvers but should have a voice in influencing policy decisions. a

The major provisions of the order -- which applies only to Executive Branch agencies, although a number of independent agencies also have set up similar offices -- call for the appointment of a senior-level official to report to the agency head on consumer problems.

In addition, the officials are to develop publications for consumers, set up complaint-handling procedures and train consumer affairs specialists. Some of the agencies also are installing toll-free numbers to handle public queries under the program.

Rep. Benjamin Rosenthal (D-N.Y.), a leader in the fight to establish a consumer protection agency, pointed out that the consumer officials won't have the power to intervene formally in legal proceedings.

"The success of this depends on the strength of the designated advocate," Rosenthal said in an interview. "The only hope we have is the right to whisper in the Secretary's ear."