A government pledge to place a new warning on aspirin packages against giving the drug to children with chicken pox or flu met a flurry of criticism yesterday at a congressional hearing that an administration source described as a "stacked deck."

While a Department of Health and Human Services proposal is expected soon, the issue has been under intense discussion in recent days, HHS sources said. HHS Secretary Richard S. Schweiker promised in June to warn about the link between use of aspirin in children with flu or chicken pox and a rare life-threatening condition called Reye's Syndrome. However, a proposed regulation has not been published yet.

Consumer critics complain that the government has delayed too long in proceeding on a new regulation before the coming flu season. But at a House Science and Technology subcommittee hearing yesterday, chaired by Rep. James H. Scheuer (D-N.Y.), a medical witnesses questioned the need for a warning.

"I believe that placing a warning label on aspirin . . . is not based on scientific evidence or on a correct analysis of available data and does not serve the welfare of children," said Dr. Heinz F. Eichenwald of the University of Texas at Dallas. He said parents of youngsters with chronic diseases such as rheumatoid arthritis are being frightened away from using the drug when needed.

Eichenwald was one of six academic experts who sent a telegram last month to HHS saying the warning was "premature." The six experts were asked to survey the evidence against aspirin by the Bayer Aspirin manufacturer, Sterling Drug Inc.

Only one outside scientist who agreed with the proposed administration action was on yesterday's witness list. Dr. Reuel A. Stallones of the University of Texas at Houston said in a statement that despite the controversy "we have sufficient information that aspirin may pose a hazard that to do nothing appears to me to be irresponsible."

Reye's syndrome is a mysterious disease among children that is fatal in about 20 percent of the cases.