The administration is finding itself under attack from opposing congressional fronts in the military budget battle that has engulfed Congress and the White House.

On one side, a few influential, defense-minded senators have demanded higher Pentagon spending as a condition for approval of the SALT II pact. On the other, the budgetary cleaver was being wielded against President Carter's fiscal 1980 military requests.

The effect of the crossfire from House and Senate, from higher spending advocates and budget-cutters was to put President Carter in a non-win position on the issue, which is at least as rich in political symbolism as it is in substance.

The Senate Budget Committee rejected Thursday a move raising congressional budget ceilings to allow for the president's pledge to NATO allies of a real, 3-percent-a-year increase in military spending.

"We don't have any new requests fom anyone about weapons waiting around to be funded," said Sen. Pete V. Domenici (R-N.M.), who sided with the majority in an 8-to-6 vote rejecting an amendment to raise the ceilings. Only a day earlier, Domenici had voted for a lesser increase in Pentagon budget ceilings to provide only for new strategic weapons.

At the same time, the House Appropriations defense sucommittee slashed $2.2 billion out of Carter's $129.6 billion Pentagon budget request, although it still is $6.5 billion above the fiscal 1979 total.

"That leaves us in effect with no growth at all on the House side," commented a Defense Department official yesterday. Inflation, he noted, has already wiped out almost half of the president's promised 3 percent increase. "And then we have senators who are demanding that growth be even higher than 3 percent," the official said, with puzzed amusement.

The move to tie substantially higher defense spending levels to approval of SALT was initiated by Sen. Sam Nunn (D-Ga.) and endorsed this week by former secretary of state bhenry A. Kissinger.

The Senate Budget Committee has estimated that Nunn's proposal for a 5-percent-beyond-inflation increase would cost $111.8 billion more than the administration's projected military spending through fiscal 1984. This would be an average of $22 billion a year through the five-year perios. The aggregate $111.8 billion increase is almost as much money as the Pentagon expects to spend for this whole budget year.

On Thursday three SALT critics, Nunn, Sen. Henry M. Jackson (D Wash) and Sen. John G. Tower (R-Tex.), sent President Carter a letter citing a "crucial" spending need foor "weapons ships, equipment and research and development," areas in which they said the Soviets "have been outspending the United States by 2 to 1."

Six weeks ago, when the fiscal 1980 defense authorization bill was approved slightly below the level requested by the president, neither Nunn nor Jackson opposed the spending proposal as inadequate. Only Tower pronounced the spending levels in the bill as inadequate during the three days of debate.

"That" a Senate Armed Service Committee aide tartly observed, "was pre-SALT."

Pentagon civilian executives said in interviews that they doubted that the extra 22 billion a year in Nunn's proposal could be wisely spent by the agency. They said there was little opportunity for spending much of the proposed Nunn divided in strategic programs. It would have to be allocated to conventional force operations, which were cut $1.5 billion by the House subcommittee Thursday, these officials suggested.

One defense official described as a "mousetrap play" the proposal by Nunn and Kissinger to tie SALT to higher defense spending. One NATO military planner said it would be possible to spend an extra $8 billion, at most, over two succeeding years for purchase of weaponry and equipment to store in Europe for a NATO emergency.

Millitray planners and defense contractors, in contrast to the civilian leadership of the Defense Department, are more confident of the opportunities to spend the budgetary bounty proposed by Nunn and like-minded political figures.

The Army would like to buy more new XMI tanks than the House Defense Approriations subcommittee was willing to approve. The uniformed Navy leadership wants to keep building $2-billion-a-copy Nimitz nuclear powered carriers rather than the administration plan for a combination of smaller oil fueled carriers and more fighters. The Air Force wants a new bomber and airlift planes. The Marines want a new jet fighter Defense Secretary Harold Brown says is unnecessary.

Defense contractors, too, have their catalogues of military hardware -- millies submarines and aircraft -- they would like to see the Pentagon buy with the higher spending ceilings proposed by Nunn.

"There are a hell of a lot of areas to spend extra billions on in the defense area," said one contractor spokeman.

North America Rockwell executives, for example, are already briefing Pentagon and Strategic Air Command officials on the merits of a bomber reconfigured to serve as a cruise missile carrier. It would be built entirely of aluminum for greater survrvability in a nuclear attack.

General Dynamics is stepping up its promotion of the stretched-out FB111 medium-range bomber, which SAC officials are already advocating as a counter to the Soviet Backfire bomber.

Both the VI and the FBIII have been turned down by Brown and President Carter.