Pummeled by questions about his support for expanded trade with the Soviet Union, Commerce secretary-nominee C. William Verity yesterday told senators at his confirmation hearing that he has "reservations" about the law that links trade benefits for that country with increased levels of Soviet emigration.

Verity's nomination to replace Malcolm Baldrige, who was killed in a rodeo accident, is expected to be approved easily by the Senate Commerce Committee next week. Most senators on the panel said yesterday they would support Verity, formerly chairman of Armco Inc., the steel manufacturer. None vowed to oppose him.

But Verity's concerns about using trade as a lever to force higher emigration levels has caused some Jewish groups to raise questions about his views. And some conservative and business organizations oppose his nomination on the grounds that more trade with the Soviets would facilitate transfers of technology with possible military applications.

At the hearing, Verity, 70, responded to questions on both issues. He said the law linking Soviet trade to emigration levels, called the Jackson-Vanik amendment after its Senate and House sponsors, the late senator Henry Jackson and former representative Charles Vanik, was "the law of the land" and would be enforced by him as commerce secretary.

"It is an important instrument for the Jewish community to use as a lever" to induce more emigration, Verity said.

In 1986, only 914 persons were allowed to emigrate from the Soviet Union, although about 5,000 have been permitted to leave the country so far this year.

If emigration levels could be raised high enough, Verity said, he would support waiving the law, which denies favorable tariff treatment and access to government credit for socialist countries that unduly restrict emigration.

"We have got to support Jackson-Vanik but we have got to find ways to increase emigration out of the Soviet Union that are not tied to trade," Verity said.

Asked if 50,000 emigrants per year, the number allowed out in 1979, would be adequate, Verity said between 15,000 to 25,000 emigrants each year probably would be enough to consider granting a waiver of the law.

That remark was not greeted with enthusiasm by organizations working for more Soviet Jewish emigration.

Pamela Braun Cohen, president of the Union of Councils for Soviet Jews, called Verity's statement "extremely troubling. We had expected that if numbers were to come up, they would be low, but I certainly was taken aback to see how low the expectation was. We are telling the Soviets they need to do very little to get substantial concessions from our government."

Jerry Goodman, executive director of the National Conference on Soviet Jewry, said Verity's figure was "on the low side," although he cautioned that focusing on numbers alone takes a too-narrow approach. At a meeting between Jewish leaders and Verity last week, the nominee eased some of their worries and said he did not favor repeal of the Jackson-Vanik provision, Goodman said. The union of councils opposes Verity's nomination, the national conference does not.

Asked about controls on sales of technology to the Soviet Union, Verity pointed out that the United States would harm its own economy by ignoring the second-largest market in the world. But he called for strict enforcement of controls in conjunction with U.S. allies who also are Soviet trading partners.

On trade, Verity said he would work to fashion an acceptable rewriting of the nation's trade laws out of the House and Senate bills, both of which include elements unacceptable to the White House. The conference to reconcile the two versions begins next week. But he did not answer a question about whether he would recommend a veto if the final bill closely followed the House or the Senate version