The information curtain that separates normally tight-lipped Soviet officials from western journalists in Moscow parted in this Swiss city today as senior Kremlin officials briefed more than 200 international journalists on human rights, arms control and other issues that will be featured in the U.S.-Soviet summit next week.

For an hour, Georgi Arbatov, director of the Moscow-based Institute for the Study of the U.S.A. and Canada, and three other Soviet spokesmen fielded questions from journalists who have descended on Geneva to cover the summit.

In the on-the-record session, they portrayed Soviet leader Mikhail Gorbachev as better prepared than President Reagan for the meeting, charged the United States with anti-Semitic acts that would "not be permitted in the Soviet Union" and dug in their heels against the Reagan administration's Strategic Defense Initiative program (SDI).

U.S. officials declined to try to counter the Soviet allegations, offering no comment and asking that they not be identified. The U.S. press center will not open until Saturday evening, when Reagan is due to arrive from Washington, they said.

Arbatov, government spokesman Leonid Zamyatin and a dozen other senior Kremlin officials flew here earlier this week and have been blitzing journalists with a series of briefings, stacks of translated press releases and Gorbachev speeches and a press luncheon.

The already high Soviet profile is certain to rise as the summit gets under way Tuesday and this small Swiss city begins to overflow with journalists.

In Moscow, spokesmen routinely decline to comment on the most basic questions about the summit, leaving the handful of locally based western journalists to their own devices for information -- even on the Soviet leader's arrival plans for the meeting. But here, where about 3,000 reporters from around the world will be hunting news eagerly from both the American and Soviet sides for their dispatches, Soviet spokesmen seem just as eager to make themselves available.

Seeking to grab attention away from the Americans, they have sparred with western journalists in defending the Soviet Union's stance on all summit-related issues. An advance team of press officials arrived here two weeks ago to test the microphones and plot out a schedule of briefings to be held at the Soviet press facility, which nearly dominates one wing of Geneva's sprawling international conference center, where journalists will gather.

The delegation accompanying Gorbachev will include some of Moscow's most experienced news disseminators: Zamyatin, spokesman for the last four Soviet leaders and former chief of Tass, the official Soviet news agency; Vladimir Lomeiko, press spokesman for the Foreign Ministry and a veteran of the Novosti information service and the official weekly Literary Gazette, and Arbatov, a frequent guest on American television who worked in the 1950s and 1960s as a journalist for several Moscow publications.

Other briefers today included Evgeny Velikhov, vice president of the Soviet Academy of Sciences and an SDI specialist, and Roald Sagdeev, director of the Institute of Space Research in the Academy of Sciences. Saturday, Middle East expert Evgeny Primakov and other Soviet foreign policy experts will conduct a briefing on regional issues, according to a Soviet spokesman. Primakov, a former Pravda correspondent, is a close Gorbachev adviser on international affairs.

Recent publicity gambits abroad have given Moscow press officials practice for competing with western news sources.

American journalists covering ceremonies marking the 10th anniversary of the Helsinki accords in Finland in August found Soviet briefers, including Anatoliy F. Dobrynin, the ambassador to the United States, more accessible and talkative than their American counterparts.

When Gorbachev visited Paris in October, he used the occasion to hold the first international press conference by a Kremlin ruler since the days of Nikita Khrushchev.

The Soviet government newspaper Izvestia said this month that "Moscow has taken over the initiative in the political psychological preparations conducted by both sides" for the summit.

Many western journalists note, however, that much of the information disclosed in briefings is a better packaged version of what was available in Soviet newspapers and on the Tass wire earlier.

In today's briefing Zamyatin said, "In the United States there are major pogroms against the Jews, and there are legal organizations against Jews." The government spokesman added that 315 Jewish places of worship had been desecrated in Brooklyn, N.Y., adding that "this would not be permitted in the Soviet Union."