Secretary of State Alexander M. Haig Jr. said yesterday that a "close accord" has been forged with West Germany about the martial law crackdown in Poland but he declined to say what follow-up sanctions, if any, are expected from the Germans and other U.S. allies.

Speaking at a press conference immediately after an apparently tough final meeting here with West German Chancellor Helmut Schmidt, Haig repeatedly emphasized that the allies have differing problems that condition their responses to the Soviet Union in the current situation.

Haig, who is preparing to meet the foreign ministers of the North Atlantic Treaty Organization in a special meeting on Poland next Monday, said he did not expect agreement then on "a uniform outcome on that very difficult issue" of anti-Soviet sanctions.

Haig was unwilling yesterday to repeat the call for "parallel steps" by the allies to complement the U.S. sanctions previously adopted by President Reagan. Official sources described this as a tactical maneuver designed to facilitate negotiations with the allies. The sources said the United States, in fact, continues to hope tangible support will result from next week's NATO meeting.

In another development, administration sources reported receipt of a letter from Gen. Wojciech Jaruzelski expressing willingness to lift martial law, release prisoners and re-establish a national dialogue that includes the labor organization, Solidarity. However, no dates or other specifics were given, and, in their absence, Washington officials consider the message to be merely "nice words" that do not change the situation. The message was handed by Jaruzelski to U.S. Ambassador Francis J. Meehan this week.

Haig's breakfast yesterday with Schmidt, the final event of the German leader's visit, followed a round of meetings with Reagan and others Tuesday in an effort to align the policies of Washington and Bonn. By publicly criticizing the Soviet Union Tuesday for the first time in the Polish crisis, Schmidt made it possible for Reagan and Haig to speak approvingly of a shared assessment with the German leader.

Despite the U.S. effort to put a positive face on the results, there was no sign that the West Germans had moved toward halting the planned Siberian-Western Europe gas pipeline, in which they have a major role, or taking any other economic or political reprisals against the Soviets. For all of Haig's public deference to Schmidt's views, sources said their final session featured blunt talk from Haig about German responsibilities to the Western alliance.

On a major point of interest to the German government, Haig made it clearer than ever yesterday that the United States intends to resume negotiations with the Soviet Union next week in Geneva on the limitation of medium-range nuclear weapons in Europe.

Moreover, Haig adopted a relatively expansive rationale for this decision, saying that the arms talks "constitute a very special category of East-West relations...because there are fundamental advantages to the West as well as the East in the continuation of a dialogue seeking control of nuclear armaments." He added that this dialogue should be interrupted only in "the most exceptional of circumstances," a definition which does not encompass the present situation.

Those statements by Haig were reminiscent of the Carter administration's rationale for treating U.S.-Soviet stratetic arms limitation talks (SALT) as a special category of East-West relations, insulated where possible from other conflicts and cross-purposes with Moscow. The Reagan administration came into office highly critical of this view and espousing the "linkage" of arms control with other Soviet-American issues.

Haig strongly suggested that he plans to go ahead with his scheduled meeting Jan. 27 with Soviet Foreign Minister Andrei Gromyko if the situation in Poland remains the same. Citing Reagan's recently expressed interest in a summit meeting with Soviet President Leonid Brezhnev, Haig said high-level communications are more, rather than less, important in times of crisis.

Haig also envisioned a U.S.-allied call for a special discusssion of Poland by the Madrid follow-up conference on the 1975 Helskinki accords. The Soviets could and probably would block such a meeting by an objection, according to officials.

If the Russians object, Haig declared, it would be "a clear signal" to the world of their position on the Polish situation.