West Germany announced a series of cutbacks and delays in its long-term military program today and indicated that it still will be strained to meet planned modernization goals during the next four years.

Completing a three-day review of West Germany's military program -- prompted by recent financing problems and increased budget-consciousness in Bonn -- Defense Minister Hans Apel said about $615 million will be saved by canceling or postponing major projects. Apel stated that he nevertheless will have to seek an additional $470 million beyond planned budgets to meet the cost of new weapons systems through 1984.

The pressure on the West German Defense Ministry to keep its budget in line contrasts with the priorty attached to military spending by the Reagan administration in Washington. The picture of West Germany trimming defense program at a time when the United States is appealing to its North Atlantic allies to increase defense efforts could become a cause of friction between Bonn and Washington.

The West German foreign minister, Hans-Dietrich Genscher, is due to leave Sunday for several days of talks in Washington. But a senior Bonn diplomatic source said yesterday that the minister will try to avoid discussion of the details to Bonn's defense budget, leaving that to Apel who himself is scheduled to visit the United States later this month.

Genscher is expected during his American tour to underscore substantial contributions that West Germany has made to Western alliance security, while pointing to two factors at least that make further major boosts in Bonn's defense spending politically difficult. One is West German public opinion, which lacks the anti-Soviet edge seen in America today and which still harbors hope for success in arms control negotiations with the Soviet Union. The second is a weakened national economy that is expected to decline this year.

In his remarks to reporters, Apel noted that his budget calculations exclude additional expenses to provide support for U.S. forces stationed in West Germany. This was requested last year by the Carter administration and seems certain to be pressed by the Reagan team. Nor do Apel's figures include compensation for unforseen price increases in weapons production.

Apel said the West German government still expects to meet timetables for all its medium-range modernization projects. These include supplying the armed forces with 1,800 ultramodern Leopard II main battle tanks, six multi-purpose frigates and 322 of the Tornado combat aircraft being built by a German-British-Italian consortium.

Apel inicated, however, that fulfillment of these plans would remain conditional on sufficient compensation for unforeseen inflationary increases in the West German defense budget through 1984.

He said the building of two more frigates would be postponed until 1987. There will also be a delay until 1986 in the start of the Patriot air defense missile system.

Moreover, Apel said plans to supply the German Army, Navy and Air Force with tank-mounted Roland antiaircraft missile systems would be limited to the Army.

A German-French plan to produce a main battle tank -- considered of special symbolic importance of Chancellor Helmut Schmidt and President Valery Giscard D'Estaing of France -- is to be reduced to developing a new tank turret. A plan to build a German-French-British tactical combat aircraft in the 1990s will be abandoned, Apel said.

This year's West German defense budget, set at about $19.3 billion, came under U.S. criticism at the end of last year for falling short of the Western alliance goal of achieving a 3 percent increase in real defense spending annually. At the time, Schmidt promised that West Germany would honor its alliance commitments, and the chancellor's aides hinted that one or more supplemental budgets might be added this year.

Appel said today that a supplementary increase to the 1981 budget could only be expected if the West German mark falls further on foreign exchange markets or if a major new rise in fuel costs occurs.

In an apparent bid to forestall criticism from Washington, Apel said West Germany intends to take on new commitments for housing U.S. troops in West Germany under the so-called Program of Hose Nation Support. This has been estimated to require a one-time cost to bonn of up to $470 million.

Bonn's review of defense programs follows the disclosure recently of substantial cost overruns on the Tornado. A parliamentary investigation into the project is under way.