Gearing up for a full-scale battle over federal spending in the new Congress, President Carter is bringing four more lobbyists into the White House specifically to protect his budget-cutting proposals from major alteration on Capitol Hill.

The creation of the special "budget task force" in the office of congressional liaison director Frank B. Moore is the latest sign of Carter's determination to push his "austerity budget" for fiscal 1980 against the opposition of some liberal Democrats and many domestic interest-groups.

The president's budget, which reportedly will trim the planned deficit below $30 billion by cutting back the normal growth of many domestic programs, does not go to Congress untill Jan. 22.

But in an effort to put its critics on the defensive, administration spokesmen last week alternated stern warnings that budget-busting could feed the fires of inflation with soothing hints that the cutbacks may not be as painful as had been feared.

In the bad cop-good cop public relations drive, presidential assistant Stuart E. Eizenstat, reputedly the most liberal of Carter's domestic advisers, warned that the "new realities" of inflation and limited resources require painful budget choices, while administration colleagues were leaking daily driblets of selective news about supposed restorations of previously rumored cuts.

But, recognizing that the politicallobbying pressures on the budget battle will grow intense once it reaches Capitol Hill, Carter last week approved creation of the special budget task force.

In personal notes to the Cabinet secretaries, Carter said the high priority he attaches to the budget battle required him to commandeer Gael Sullivan, a Commerce Department lobbyist, and Sargent Carlton, who had a similar role for the Interior Department, as "detailees" for up to six months on Moore's staff.

Two other recruits for the White House team are to be named shortly, according to William Cable, deputy to Moore -- who is traveling abroad.

Cable said the buildup resulted from the realization that "if the president's going to take all the heat and criticism on the budget, we'd better mobilize to get it passed."

"You can't really expect the departments to lobby effectively against pressures to expand their own budgets," Cable said. "For the bureaucrats, turning down money is not a natural act."

"The only other possibility was to have OMB [the Office of Management and Budget, the arm of the executive office that draws up the budget] lobby against budget-busting," Cable said. "But OMB has a bad reputation on the Hill. They're the green-eyeshade guys, who know the numbers but have no heart.

"So we decided that if the president's budget was going to be protected, we'd have to organize something here in the White House.

Cable said the creation of the special lobbying unit was cleared with House Speaker Thomas P. (Tip) O'Neill Jr., (D-Mass.) and Senate Majority Leader Robert C. Byrd (D-W.Va.), both of whom are regarded as essential allies for the president in the coming fight.

O'Neill is particularly crucial. Budget resolutions have had hard going in past years in the House, when Republicans voted as a bloc against what they regard as excessive spending and liberal Democrats defected because they felt domestic programs were being trimmed too far.

In addition, O'Neill has political links both to Sen. Edward M. Kennedy (D-Mass.) and Boston Mayor Kevin H. White, both leading critics of Carter's proposed cutbacks in urban and welfare programs.

But White House officials claim the speaker accepts Carter's benchmark of a deficit below $30 billion as a reasonable target and will work with him to that end.

In order to soften up the opposition, the White House last week was playing a double propaganda game.

On one hand, Eizenstat, newly converted from his once-firm opposition to any cutbacks in social programs, was telling liberal Democrats they must trim their demands in line with the "new realities," and warning that if they don't, "the new realities will have to take precedence."

On the other, officials began leaking reports of "restorations" from Carter's earlier cutback plans that were portrayed as victories for the liberals, even though they left spending totals far below the levels needed to continue programs intact amid high inflation.

In the most ballyhooed of these, White House officials announced that Carter had "restored" $2 billion in jobs, health, education and urban aid money his budget makers earlier had sought to cut.

However, despite the restorations, Carter still plans to slash the number of government-financed jobs to 540,000 this year, declining to 425,000 by late 1980 -- still down sharply from the 625,000-job level in force this year. Aides say fewer jobs are needed now that unemployment is down.

Some other examples:

The controversial "countercyclical revenue-sharing" program -- which provided $500 million in urban aid during fiscal 1979 -- will be replaced by a visibly scaled-down $250 million plan that will channel the money almost entirely to high-unemployment cities.

The White House "restored" all or part of many of the deep cuts OMB had planned for health programs, after an appeal by Carter rival Kennedy. But figures indicate that several programs still will be eliminated, and many will get less than in fiscal 1979.

Carter "restored" modest amounts in his education budget for fiscal 1980, with the result that the $11.1 billion total will be about $1 billion above this year's program -- but that includes extra money for Congress' new expansion of federal college scholarship programs.

Moreover, insiders say special-interest groups probably can look forward to even deeper-than-expected cutbacks in some of the less-sensitive existing programs -- reductions budget makers say are necessary if only to allow room for Carter's proposed boost in defense spending.

Carter has decided to propose raising defense outlays by almost the full 3 percentage points beyond inflation to $122.8 billion.

Eizenstat's speech last week continued a theme that had been outlined earlier by Carter, Vice President Mondale and Health, Education and Welfare Secretary Joseph A. Califano Jr.

Last Oct. 24, in his televised address on inflation, the president promised "tough restraints on federal spending" and established the budget goal of reducing the "deficit to less than one-half of what it was when I ran for office -- to $30 billion or less."

A month later, he warned the National League of Cities that "there will be little money for new initiatives next year," and said the budget "will disappoint those who do not take inflation seriously... [and] who expect constantly expanding federal aid."

Califano, a White House assistant during the creation of much of the Great Society legislation, echoed the new theme in an address to the National Press Club, saying that today, "the challenge for the American liberal is the challenge of austerity."

And when Kennedy threw down the gauntlet to the administration at the Democrats' midterm conference in Memphis in December, warning that Carter's budget cuts might be as divisive for the party as the war in Vietnam was a decade ago, Mondale replied the next day that unless Democrats supported Carter's budget-cutting moves, inflation would drive them from power as surely as the Vietnam war had in 1968.

The administration's hard-line stance appears to be working -- so far. While liberals still are grumbling privately, there's been no open challenge yet to the president's new budget proposals. Most groups seem assuaged -- for the moment -- by the "restorations" Carter has made.

But some observers suggest that may last only until they see the final budget numbers in detail. The backlash is expected to begin Jan. 22, when Carter unveils the fiscal 1980 proposals, and some predict it could turn into the biggest battle of this session.

The skirmishes are scheduled to begin in early April, when the House and Senate Budget committees begin working on a draft of the fiscal 1980 congressional budget resolution -- a first-time-'round "target" that will set parameters for congressional appropriations committees.

Under the new congressional budget procedure, Congress is supposed to approve formal budget targets by May 15, and then revise them again in September. Although only the second target becomes a binding spending ceiling, the early vote -- particularly in the House -- could be hardfought.

Liberals already have served notice that they will make the budget issue a rallying point in the coming session, and the chairmen of the two congressional budget panels have warned that Carter's cutbacks will be scrapped if the economy falls into a recession.