West German Chancellor Helmut Schmidt pledged solidarity with the U.S. position on Afghanistan and Iran today and said his country would have to make "economic sacrifices" to support its American ally.

Schmidt did not, however, discuss specific reprisal measures being comsidered by West Germany and stressed that any action taken would be careful, cautious and in concert with other allies. Moreover, the chancellor indicated that Bonn's primary response to the Soviet invasion of Afghanistan would be to pursue diplomatic and economic initiatives in Turkey, India and several Persian Gulf states.

[In London, British Prime Minister Margaret Thatcher told Parliament she has not yet made a "firm decision" on British participation in the 1980 Summer Olympics, although "we certainly favor the principle of removal of the Olympics from Moscow" to another venue in retaliation for the Soviet invasion of Afghanistan.]

Schmidt in a major policy address to the West German parliament, issued his clearest statement since the start of the Soviet invasion on where Bonn stands in light of the widening rift between Washington and Moscow.

Above all, Schmidt said, West German security interests require solidarity with the United States. Nevertheless, he reiterated his intention to maintain a dialogue with the Kremlin and reaffirmed plans to meet later this year with Soviet President leonid Brezhnev and East German leader Erich Honecker.

"Especially in difficult times, there has to be contact," Schmidt said.

The speech reflected the sharpening of the West German position that has taken place in recent days. At first, reluctant to embrace retaliation against the Soviets and concerned about possible U.S. overreaction, Schmidt today backed Washington's view that "a violation of international law cannot be without consequences."

He pledged Bonn's support for reprisals within the framework of the European Economic Community and the allied trade coordinating authority known as COCOM, which controls the export of high-technology goods to the Soviet Bloc.

With regard to Iran, Schmidt further stressed West German-American solidarity by stating that if the United States considered it necessary to impose tougher measures against Tehran, "then it can rely on the support of West Germany as an absolutely trustworthy ally and friend."

"We know this will mean that we will also have to make economic sacrifices," Schmidt added.

According to West German officials, this clearer commitment to the American cause goes along with -- and was partly encouraged by -- both the restraint shown by President Carter in his handling of the Iranian crisis so far and by the more moderate approach taken by the United States towardrd its European allies this week in negotiating a response to the Soviet invasion.

Once hopeful of achieving joint and prompt NATO and Common Market actions against the Soviets, U.S. officials have since acknowledged differing national interests and trading patterns among the allies that inhibit them from acting jointly or quickly.

In the particular case of West Germany, U.S. officials -- notably Deputy Secretary of State Warren Christopher here yesterday -- also have endorsed Bonn's special interest in keeping lines of communication open to Eastern Europe.

But while American and West German interests appear more in line, Schmidt's statement, which was the opening shot in a parliamentary foreign policy debate, was attacked by the opposition Christian Democrats as still too open toward the Soviets.

Christian Democratic Union chief Helmut Kohl accused Schmidt of retaining illusions about detente and said he was dangerously close to "the zone of political dreaming."

"The question is not to save the destroyed illusions of detente, but to secure peace in the world and with that to secure our peace and our freedom," Kohl said.

At the same time, observers noted that the ensuing day-long discussion between other Christian Democrats and members of the ruling Social Democrat-Free Democrat coalition was tamer than recent exchanges have been, signaling that West German political circles may be reaching a general consensus on foreign policy.

In his speech, Schmidt, whose Social Democrats inaugurated the West German policy of ostpolitik -- seeking better relations with Eastern Europe -- 10 years ago under the leadership of Willy Brandt, defended the policy as "not a policy of appeasement."

He said that the gains made by that policy thus far -- the repatriation of thousands of Germans from the Soviet Bloc countries, the increase in East-West trade, and the reduction of tensions in Central Europe and the divided city of Berlin -- must be preserved. He also spoke of the possibility of further disarmament talks, despite the U.S. decision to table consideration of the SALT II treaty.

"We will not let what we have established in defense and detente policy in the past 10 years be reduced or dismantled," the chancellor said.

Striking a theme that has become a favorite of his, Schmidt said German actions in times of world political turbulence should show "careful thought" and a "quiet performance."

In this regard, Schmidt made no mention of possible unilateral economic sanctions against the Soviet Union, and government officials confirmed that none are being considered, partly because of the fear here that any such reprisals would leave West Germany very vulnerable.

West German trade with the Soviets has quadrupled in the past decade, and some key industries are dependent on the Soviets for vital raw materials. An estimated 14 percent of the natural gas used here comes by pipeline from the Soviet Union. The Soviets also supply 38 percent of West Germany's enriched uranium.

Bonn's exports to the Soviet Union last year topped $3 billion. Officials say that a trade war with the Soviets would jeopardize at least 70,000 jobs at a time when unemployment is already about 900,000.

Moreover, the West German business community has been opposed to trade reprisals, expressing skepticism about the effectiveness of such actions.

Schmidt said that in keeping with U.S. requests, West Germany will at least participate in whatever reprisals are agreed to by the European Community and will go along with a tightening of COCOM rules now under consideration of limit further what high technology and stategic goods can be exported to the Soviet Union by member European countries and Japan.

Beyond that, Schmidt stated that the Bonn government would concentrate on certain diplomatic and aid actions.

Schmidt said India would continue to receive a large amount of development aid from West Germany, and he announced aid to Turkey would be stepped up.

Common Market officials further disclosed that West Germany has taken the initiative in accelerating two-year-old talks between the community and Yugoslavia on a new cooperation agreement.