Congressional budget negotiators from both parties predicted yesterday that they would achieve an accord with the Reagan administration this week on reducing the federal deficit by about $30 billion, but said the package will include cuts in popular retirement programs only if the president and the top leaders in Congress actively support it.

House Majority Leader Thomas S. Foley (D-Wash.), who has chaired the budget talks that begin their fourth week today, said yesterday on ABC's "This Week With David Brinkley" that the discussions will produce a multiyear compromise package before Friday, the date when the federal budget will automatically be cut by more than $24 billion under the nation's revised balanced-budget law.

But Foley, repeating the ground rules established by President Reagan when the negotiations began, said that the evolving compromise package of about $30 billion won't include reductions in Social Security and other retirement benefits "unless the rules are changed again."

Any change, Foley said, would require "a joint agreement" by Reagan, House Speaker Jim Wright (D-Tex.) and Senate Majority Leader Robert C. Byrd (D-W.Va.).

Other lawmakers involved in the talks, however, said that even with an agreement by the president and the Democratic leaders in Congress it would be extremely difficult to get through the House and Senate a package that includes Social Security.

"It's ideal for legislators and the executive to hold hands and jump in the water together," said Rep. Dan Rostenkowski (D-Ill.), the chairman of the House Ways and Means Committee in an appearance on NBC's "Meet the Press." But Rostenkowski said "I doubt very much that we can get the votes on the floor of the House to do that."

House Minority Leader Robert H. Michel (R-Ill.) agreed, saying it would be "just about nigh impossible politically" to pass a deficit reduction plan that cuts into the inflation allowances scheduled for Social Security recipients.

When the congressional and White House negotiators completed their last session on Friday, they were close to an agreement on a plan to reduce the fiscal 1988 deficit by about $30 billion. It was expected to include about $2 billion in savings achieved by some form of delay in cost-of-living allowances for Social Security recipients, other federal retirees and government employes.

Foley and other lawmakers involved in the negotiations have repeatedly said that any inclusion of Social Security benefit reductions would have to come about through a form of "immaculate conception" in which no lawmaker took responsibility for proposing the reductions. Though the members of Congress played down the chances, they suggest Social Security changes might occur this week.

"It's going to require the president and the leadership saying yes to it almost at the same time or it can't be done," said Sen. Pete V. Domenici (R-N.M.), ranking Republican on the Senate Budget Committee who appeared on the same show as Foley. But Domenici also predicted that "we'll get something by Thursday and it will be fair to everybody," a signal that the package is likely to include postponements in cost-of-living allowances.

Domenici said it is possible to construct a deficit reduction package without including COLAs, but said it would require "an awful lot of giving on the domestic programs that I don't see those in this conference willing to do . . . . The $64 question is, if we can't put that other package together, will the leadership get together and decide that the rules are to be changed. I'm not sure."

Reagan is to be briefed today on the emerging agreement that would also produce a second-year reduction in the deficit of between $45 billion and $50 billion. The president is scheduled to address the U.S. Chamber of Commerce on Thursday, the day when many of the budget negotiators expect a final agreement on a deficit reduction package.

The plan now under study would raise taxes by about $10 billion, cut defense spending by close to $5 billion, reduce discretionary domestic spending by $2.6 billion, and trim entitlement programs such as Medicare, farm payments, student loans and retirement allowances by about $5 billion. Other savings would come from refinancing of federal loans, user fees, more vigorous tax collections and savings on interest on the national debt.