With federal spending already surging well beyond the total Congress voted just four months ago for this fiscal year, House and Senate Budget committees are digging in to force spending cuts.

This week the Congressional Budget Office provided the two committees with new estimates which suggest that spending this year will run about $12 billion higher than approved last fall, in part because of inflation, which automatically increases the cost of many large benefit programs -- food stamps, for example, and Medicare.

Under its own budget rules, Congress now has two choices: trim away the excess spending, or vote explicitly in favor of the higher budget total and the larger deficit that this spending entails. Neither course is comfortable in this election year.

But unless it does one of these things, Congress faces a procedural crisis. Any bill that would lift spending beyond the agreed-upon total can be stymied by a single dissenting member on procedural grounds.

Among bills in this potential jeopardy is one to finance last fall's federal pay raise, and another to keep the Agriculture Department from running out of food stamp money.

Neither budget committee has decided exactly what course it will now take, and the likelihood is that, sooner or later, they will give some ground and propose that the spending total be raised.

But committee sources said yesterday it is unlikely a new budget resolution will be proposed to allow all the excess 12 billion to be spent. Some cuts will be insisted on.

As part of its campaign to force down the spending totals, the House committee made public yesterday a CBO compilation of budget areas where it could be argued that spending should be cut or special tax breaks eliminated. The laundry list of potential savings totaled more than $50 billion for the first year and $544 billion over five years.

Almost none of the examples, such as taxing a portion of Social Security benefits, are new and most are highly controversial. Even the committee chairman, Rep. Robert Giaimo (D-Conn.), said he would oppose making many of the cuts.

But both the House and Senate committees intend to try to force Congress to begin to choose some existing programs for cuts, an effort that has produced few results in the past. This year, House committee members vowed yesterday, things will be different.

Giaimo said a number of what the committee calls legislative savings proposals "have a real chance this year. Admittedly it will be difficult, but we have to face up to this or admit we aren't going to do anything about spending."

The chairman and other committee members said they expect Congress to go along with some cost-saving revisions in food-stamp administration, Small Business Administration disaster loans, and impact aid for school districts with children of federal employes, among others. Less certain are a reduction in revenue sharing with the states and the Carter administration's embattled plan to hold down hospital costs paid by Medicare and Medicaid.

President Carter proposed $5.6 billion worth of such legislative savings in the fiscal 1981 budget he sent to Congress last month.

The first confrontation between the budget committees and the backers of the programs they would like to cut will come in April when Congress has to try to reconcile accumulated spending with the $547.6 billion spending limit for 1980 that it set in its budget resolution last fall.

In the case of the federal pay raise, the administration has proposed a $4 billion supplemental appropriation assuming that government departments and agencies would, in general, absorb 18 percent of the pay raise by cutting other outlays. The budget resolution adopted last fall assumed a 40 percent offset.

Any new resolution could again insist on that sort of offset, a Senate committee source said, or perhaps not leave room for other spending increases on which Congress has not yet completed action, such as countercyclical revenue sharing for parts of the country with unusually high unemployment.

Carter's revised 1980 budget called for a $39.8 billion deficit, up from the $29.8 billion deficit in last fall's resolution. The committees' strategies point to a much smaller increase. Inflation has also boosted revenue estimates, so Carter's deficit increase was smaller than the increase in outlays.

Another reason there is no room left under the spending ceiling is that Congress assumed $3.6 billion in legislative savings would be achieved this year. So far, none has been.

The Senate voted, 90-to-6, last year to require legislative committees to propose cuts if spending were going to exceed the resolution's ceiling. The House refused to require this. But the entire debate over this reconciliation process will be removed when any new resolution comes to the floor.