Health and Human Services Secretary Richard S. Schweiker yesterday rejected requests by the country's major organizations on aging that delegates to the 1981 White House Conference on Aging be permitted to vote separately on committee reports at next week's gathering.

"It is simply not feasible," Schweiker wrote in a five-page letter to Jacob Clayman, president of the National Council of Senior Citizens, "to have 2,266 delegates vote in plenary session on scores of recommendations or many sets of recommendations in a 3 1/2-day conference."

Clayman, who along with leaders of other organizations on aging has suggested that they may walk out of the conference unless changes are made in rules Schweiker was considering, characterized Schweiker's letter as a "nice puffery sheet." Clayman said Schweiker had presented as concessions or compromises items never at issue.

"The main issue that we've been concerned about remains unresolved or was resolved by Schweiker in a negative fashion, and that is that there be an opportunity for debate and a vote on issues about which there has been substantial disagreement on the committee," Clayman said.

Representatives of organizations on aging have expressed concern that since the administration took over responsibility for the conference,, an effort has been made to appoint new delegates and to arrange the conference's 14 committees to reflect administration policies rather than advocating positions and programs to benefit the elderly.

Rules approved by Schweiker for the conference, which opens Monday, will permit discussion, debate and voting in committee meetings. On any issue on which at least 20 percent of the minority disagree with the majority position, a minority report can be filed.

The conference as a whole will not be permitted to vote on a committee's report. The entire conference will be presented the entire body of committee reports and be asked to approve or reject them all in a single vote.

Without focusing on a particular substantive issue, the leadership of the principal organizations on aging has made that single vote the target of efforts to reshape conference rules. Otherwise, Clayman said yesterday after reading Schweiker's letter, about 7.5 percent of the delegates--a majority on a single committee--may be able to dictate a position contrary to the wishes of a majority of conference delegates.

"The letter is a clever public relations gimmick," Clayman said. "And the issue that has separated us for long months is the one that he has rejected out of hand."