West German Chancellor Helmut Schmidt yesterday welcomed President Carter's decision to defer production of neutron weapons but coupled this with a warning that U.S.-West German relations, already strained, do not need any more burdens at this time.

The chancellor's remarks, made to a closed meeting Tuesday of parliamentarians from his Social Democratic Party and published here yesterday, reflect Schmidt's first real public acknowledgement of the strains that have built up between the two key NATO allies.

The candid and detailed statement revealed for the first time the private indications Schmidt had given the Carter administration that West Germany would accept deployment of neutron weapons on German soil.

It also showed, however that Bonn had imposed conditions, not only a requirement that the decision be made jointly by the Atlantic alliance. but that at least one other country should have the controversial weapon placed on its soil.

The White House, however, has always wanted a clear public statement from the Europeans that they would allow deployment if the United States decided to produce the neutron warhead. Such open assurances were not forthcoming before the president announced his decision last Friday to defer production.

The new burden in relations with the United States that Schmidt is seeking to avoid has to do with what he called "worries" among the nine Common Market countries that the new U.S. nuclear nonproliferation act will give the president a veto over shipment of enriched uranium fuel to Europe and thus a stranglehold over the lucrative European nuclear reactor export industries.

The matter is of great importance to Western Europe and Schmidt said he "assumed that President Carter will keep his agreement made at the London summit meeting last May to continue deliveries at least for a two-year period" while improvements in nuclear safeguards are discussed.

The new law, which is designed to help halt the spread of nuclear material and nuclear technology, requires the United States to renegotiate fuel contracts with foreign countries. The West Germans claim that they have been reassured by the White House that the law will not be used to block their multi-billion dollar deal with Brazil, which Carter has tried to kill by earlier pressure on Bonn.

Schmidt said he did not expect the difficulties with the new law to be a cause for lasting tension between the United States and the Europeans.

We do not need such a burden at this time," the Chancellor added, since disputes "over the dollar and the neutron weapon have already caused to much unrest."

The chancellor's comments were also the first since President Carter's decision on the neutron weapons. That decision caused an enormous political jolt in Bonn because Schmidt's center-left coalition had edged closer to the politically risky position of publicly endorsing a U.S. go-ahead on the controversial weapon at the very time that the White House decided to wait.

In yesterday's statements, Schmidt said he considers Carter's decision to defer building neutron weapons pending developments on Soviet attitudes toward the strategic arms limitation talks (SALT) as a generally positive one that gave the United States and the West potentially more flexibility for negotiating with the Soviets.

He suggested the decision would have been even more welcome without all the fuss," and apparent reference to the manner in which the decision was made and the political and press uproar that followed here and in other Western capitals.

The chancellor has been under fire here from conservative opposition leaders for not making it known publicly, as the White House sought, that the West Germans would support deployment of the neutron weapon if necessary after a U.S. decision to build them.

The conservative opposition parties, in effect, are trying to blame Schmidt for the president's decision, which could ultimately keep the weapon - seen as an important counter to Soviet tank armies - out of the NATO arsenal. The conservatives yesterday put forward a motion to be presented in a major parliamentary debate tomorrow which calls on the government to openly express its readiness to allow the weapon to be stationed in West Germany.

Toward off that pressure, the government distributed Schmidt's remarks to show what the Bonn position had been.

"The German government has made it continually clear to the Americans since the fall of 1977 that it would not take an active role in the decision to produce the bomb," Schmidt said.

"We are not a nuclear weapons country and we do not want to give the impression of using the back door to make nuclear weapons decisions."

"We further told the U.S. government that if a positive decision is made on the weapons, we would want to see it included in the arms control talks. The Americans are of the opinion that such action would only be impressive with a definite go-ahead for production behind it," he said.

Bonn then put forward its conditions: Joint agreement on deployment and that the neutron weapons "would not be stationed only on German territory."

"This position has not been changed by the federal government," the chancellor said.

Schmidt said the question of arms control would also be prominent next month when Soviet President Leonid Brezhnev makes a long-delayed trip to Bonn.

Although Schmidt says he plans to express grave European concerns to Brezhnev about the Soviet arms buildup in Central Europe, the absence of a Bonn-supported decision to produce the neutron weapon is apt to provide a better atmosphere for the West German-Soviet talks.

Moscow has conducted a heavy campaign against Bonn to try to stop the neutron weapon deployment, and a better atmosphere in the forthcoming talks could improve West German ties with the Soviets. Except for growing trade, Bonn-Moscow relations have been stagnant for several years.

The Brezhnev visit here could also entail discussion in another of the areas that have thrust the Carter administration into dispute with several of its key allies.

There have been reports that both Schmidt and French President Valery Giscard 'd Estaing are privately so uncertain about White House and congressional plans in the nuclear fuel area that both countries may discuss increasing orders from the Soviets as a headge against the new American law.