The leader of the nation's largest federal employe union, two area congressmen with large constituencies of federal workers, and the Reagan administration's chief personnel officer agreed yesterday that government workers have a more generous retirement system than those available to most people in the private sector.

But the panel split over President Reagan's proposed retirement changes. The union official and the congressmen argued that retirement benefits for the government's 2.3 million full-time workers must be considered alongside federal pay, health benefits and job-enjoyment factors that they said cannot be compared with the private sector's.

"It's true, retirement is more generous," said Rep. Steny H. Hoyer (D-Md.), " . . . but it's offsetting pay that has fallen behind."

Hoyer, Rep. Frank R. Wolf (R-Va.), Donald J. Devine, director of the Office of Personnel Management, and Kenneth T. Blaylock, president of the American Federation of Government Employees, discussed federal retirement during a luncheon forum sponsored by The Washington Post.

Robert Mueller, executive director of Taxpayers for Federal Pension Reform, and Edwin C. Hustead, former chief actuary at OPM who now directs actuarial consulting services at Hay Associates, also participated in the discussion.

An edited transcript of the forum will be published in The Post on May 11.

OPM's Devine said that the Reagan administration--which has proposed raising the retirement age and wants federal workers to contribute more to their retirement fund--thinks the present system's annuities and cost-of-living adjustments are too attractive.

"Right now, employes can't afford not to retire," Devine said.

Mueller said that 80 percent of the federal worker retirement system is funded by taxpayers and argued that private sector employes should not have to pay for retirement benefits that are better than their own.

But Hoyer, Wolf and Blaylock challenged much of the reasoning behind the Reagan proposals, saying that additional benefit cuts will hurt recruitment and further damage employe morale, which they said is at an all-time low.

"Of course taxpayers are bearing the burden," Hoyer interjected during one of several heated exchanges among the participants. "These are the taxpayers' employes."

Blaylock, whose union represents 600,000 federal workers, said the retirement issue could not be addressed "in isolation." Employes, he said, "put up with" pay caps, RIFs (reductions-in-force) and cuts in health insurance benefits because they have been able to count on early retirement and generous annuities.

Even so, Blaylock added, more than 75 percent of eligible federal employes don't retire until age 61. Under present law, employes with 30 years' service can retire at age 55. The Reagan administration proposes to reduce pension benefits of workers who retire before 65.

Wolf, saying federal workers no longer have much confidence in the figures coming out of OPM, urged support for his proposal to set up a bipartisan "blue ribbon" panel to study retirement and other federal employe issues "from the same data base." He suggested former president Gerald R. Ford and David Henderson, former chairman of the House Post Office and Civil Service Committee, could head such a study.

Devine argued, however, that it is better to "make the changes and get the thing behind us" than to "upset" employes by making them wait a couple of years for the results of a study.

"They're upset now," Wolf replied.

Devine said he and Blaylock agreed, in theory, that overall benefits for federal workers should be comparable to those in the private sector. They just disagreed, he said, on whether federal benefits are better.

"I think they're better," Devine said.

"AFGE will support any system based on comparability with the emphasis on total compensation," Blaylock said.

But he said federal workers "are not going to sit back and be attacked and used as scapegoats."