With only a week to go before a new fiscal year begins, the Republican-controlled Congress remains deadlocked over most major spending bills, and its leaders are preparing legislation to avert a politically disastrous government shutdown.

Despite pledges by House Speaker J. Dennis Hastert (R-Ill.) and others to keep to the normal congressional calendar, unresolved differences over spending levels and issues such as the environment, farm policy and family planning make it virtually certain Congress will be unable to complete work on the budget by Oct. 1, the start of the new fiscal year.

Just yesterday, for instance, House and Senate negotiators put off consideration of next year's agriculture spending bill becauses of disputes over dairy regulations and sanctions on farm exports to terrorist countries. Lawmakers working on the defense appropriations bill were struggling to come to an agreement on how much funding to include for the F-22 fighter plane.

To buy time to resolve such thorny issues, GOP leaders want Congress to adopt a temporary plan next week that would fund the government for three weeks at this year's spending levels.

Hastert remains determined that Congress will adjourn by Oct. 29, aides said. But a skeptical Rep. David R. Obey (Wis.), the ranking Democrat on the Appropriations Committee, warned that the budget troubles are so severe that "we'll be here past Thanksgiving, past Christmas" to finish up.

At issue are the 13 annual spending bills that are essential to the day-to-day operation of government. Only four of these bills, the least controversial, have been approved by Congress and sent to President Clinton for his signature.

The rest, including major bills funding health and social programs, veterans and housing initiatives and the Pentagon's budget, face varying obstacles, not the least of which are threatened presidential vetoes because of what the administration deems inadequate funding.

But congressional Republicans are also finding it difficult to make good on a promise to fund government programs next year without dipping into the vast Social Security trust fund. For years, dating to the Johnson administration in the late 1960s, the federal government has tapped surpluses generated by Social Security taxes to cover deficits in the rest of the government.

With the economy booming and budget surpluses projected to grow, however, Republicans have promised not to touch Social Security any longer -- and to keep those funds available to shore up the giant retirement program. By elevating this once-obscure budget issue to a top legislative priority, Republican leaders believed they could box in Clinton by making it impossible for him to demand additional domestic spending without appearing to be raiding Social Security.

But Clinton eluded their trap by offering alternatives for increased spending, including an increase in the tobacco tax and government user fees, that would leave Social Security unscathed. Now it is the Republicans who find themselves in a box, unable to pass spending bills satisfactory to their own rank and file or the administration without reaching deep into the Social Security funds.

"There is no graceful way out," said Robert D. Reischauer, a former director of the Congressional Budget Office.

House Minority Leader Richard A. Gephardt (D-Mo.) yesterday charged that Republicans were resorting to "cheap budget tricks" to try to hide the fact they were well on their way to spending $30 billion of the Social Security trust fund in the coming fiscal year. He and Senate Minority Leader Thomas A. Daschle (D-S.D.) urged the Republicans to reconsider Clinton's proposal for a tobacco tax increase.

Republicans have dismissed a tax increase, but in their desperation to squeeze spending without touching Social Security they have embraced or considered a number of controversial budget tactics.

Those strategies include declaring the 2000 census an "emergency" and thus exempt from the spending limitations; proposing to delay payments of the earned-income tax credit to working poor families; attempting to rush $5.5 billion of emergency farm relief out the door before Sept. 30 so that it wouldn't be counted against the 2000 budget; and putting off billions of dollars in education programs until the first month of fiscal 2001 to skirt the 2000 spending limits.

Republican leaders recently dropped the earned-income credit idea in the face of Democratic and administration criticism, and yesterday the leadership declared unworkable the proposal to speed the delivery of emergency assistance to farmers.

But the House Appropriations subcommittee with jurisdiction over labor, health and education programs is scheduled to meet today to vote on a bill that would delay spending $15 billion for education and Head Start until the following fiscal year. The plan would also designate a portion of funding for the low-income energy assistance program an "emergency."

"We can move a bill and we can choose the congressional priorities for spending or we can simply let the president sit down at the table and act as a legislator and negotiate every line item," said Rep. John Edward Porter (R-Ill.), chairman of the subcommittee.

A House GOP leadership aide acknowledged yesterday the Republicans were in a tough bind. But leaders emphasize they prefer the current situation -- in which they are haggling over a fixed amount of funds -- than the kind of freewheeling debate that could have occurred if they agreed early on to violate existing spending restrictions.

"This is a good box for us to be in because what it ultimately does is limit spending, which is our goal," said John Feehery, a spokesman for Hastert. "If we didn't have this box, the president wants to spend a significant amount of the Social Security surplus."

All sides agree that a repeat of the 1995 government shutdown, for which Republican recalcitrance was largely blamed, is unlikely. Clinton will use today's ceremony to veto the GOP tax cut bill to increase pressure on Congress to steer more money to Medicare, education and other administration priorities, White House aides said. The president will signal that there is room for compromise on a smaller tax-cut package, they said, if the Congress will accede to his proposals such as adding a prescription drug benefit to Medicare.

"There will be a pretty stark reminder that they are way behind on the work they have to do on the budget and the failure to confront Medicare," said White House spokesman Jake Siewert.

Staff writer Charles Babington contributed to this report.