Defense Minister Manfred Woerner said today that the Reagan administration should not expect major increases in West German military spending in the near term under the new conservative Bonn government.

But, apparently eager to do something tangible to back up a promise to stabilize U.S.-German relations, Woerner hinted he would announce an expanded German contribution to NATO's infrastructure fund during his visit to Washington next week.

Touching on a wide range of alliance matters in an interview, the minister confirmed that unpublicized West German preparations to accept new U.S.-made Pershing II nuclear missiles at the end of 1983 were "on schedule." He reaffirmed Bonn's willingness to follow through with the deployment if U.S.-Soviet arms reduction talks fail, but said he expected more "serious protests" in West Germany before the missiles arrive

Commenting on recent calls by Gen. Bernard W. Rogers, the NATO commander in Europe, to pay more for expensive new conventional armaments, Woerner said he also favored greater alliance emphasis on conventional weaponry to lessen dependence on the nuclear deterrent. But this, he added, was a long-term proposition, and, stressing the continued importance of nuclear weapons to deter war, Woerner cautioned Rogers and others against raising public expectations that a prospective conventional weapons buildup might alleviate the need in the short run to modernize NATO's nuclear arsenal.

West Germany, which commands the largest European conventional military force in the North Atlantic Treaty Organization, has been a primary target of U.S. calls for more allied defense spending. Woerner himself, while in the opposition as a Christian Democratic member of parliament, frequently criticized the government of former chancellor Helmut Schmidt for cutting the defense share of the budget from over 25 percent in the late 1960s to 18 percent now.

Yet the 4.8 percent increase in the 1983 defense budget approved by the new Cabinet last week is barely enough to keep up with next year's projected inflation rate. It includes only a symbolic $40 million more than the Schmidt government had planned to spend before its ouster Oct. 1.

Woerner defended his new budget today, saying it is the largest spending increase any major Bonn department got and represents a particularly significant commitment in view of the government's fiscal austerity program.

"We'll do all that is possible to increase our defense efforts," the minister asserted. "But we inherited a financial situation that is absolutely desolate."

Citing a prolonged recession that has produced post-World War II records of unemployment and bankruptcies in West Germany, Woerner said it would be some time before the new center-right coalition could set about reversing past trends in defense spending. "Given the actual situation, it is impossible to correct it in one or two years. Impossible. Everyone will understand that," he said.

Reports by senior military staffers, leaked recently to German correspondents, have warned of serious deficiencies in national defense resulting from slowdowns in the purchase of sophisticated new equipment. But Woerner, 48, a longtime military affairs specialist who flies jets as an Air Force reservist, stated that procurement had in fact been overemphasized at the expense of certain personnel factors.

In the future, he said, training and what Woerner called "leadership and the social situation" of the German armed forces would be given higher priority. The 1983 budget, for instance, already reflects a shift in funds for promotions and for hiring more volunteer career soldiers.

At the same time, Woerner said he would postpone until the end of next year a decision on what to do about a threatened loss of military manpower as fewer youths become available for the draft. A special commission has recommended extending the period of conscription from 15 to 18 months or allowing women volunteers into the German armed forces, both politically sensitive options.

Aside from more money for NATO infrastructure projects, Woerner showed no inclination to fund other standing U.S. defense requests. These include a $1 billion plan to modernize American troop facilities and restation some combat brigades closer to the East-West border here.

In addition, Washington is pressing West Germany and other allies to take up more of the general defense burden in the NATO area so as to free U.S. resources for beefed up out-of-area defense efforts, particularly in the Persian Gulf.

Woerner declined to specify what his government's new infrastructure contribution would be. "I'll bring it over there," he said, referring to his Washington visit.

Expansion of the infrastructure fund, a common NATO fund which pays for such operational facilities as airports, command posts and storage depots, was resisted by Schmidt's government. A U.S. diplomat here said a commitment to pay more by West Germany, which like the United States accounts for about a quarter of the total fund, would remove an "irritant" in U.S.-German relations and be "a good sign."