Japan announced today a new series of steps to give foreign products greater access to the Japanese market in a bid to smooth the way for Prime Minister Yasuhiro Nakasone's visit to Washington next week.

Adopted at a special meeting of Nakasone's key economic ministers, the measures promised no immediate reduction in the huge $20 billion U.S. deficit in its trade with Japan.

The government did, however, outline a broad strategy for dismantling the labyrinthine customs, product standards and testing procedures that American business people complain bar them from competing in lucrative markets here.

The new round of trade measures included a virtual repackaging of action taken by the Nakasone Cabinet late last month to reduce or eliminate entirely import duties on 47 farm commodities and 28 industrial goods and to expand import quotas for a half dozen agricultural items, including fruit pure'e, non-citrus fruit juice, tomato juice and ketchup.

The earlier announcement, which became official policy today, also reduced tariffs on imported tobacco products from 35 percent to 20 percent. Officials said today that the tariff cuts would become effective April 1, bringing to 323 the number of tariff cases Tokyo has acted on since last May.

In a related development, the government promised to allow U.S. cigarettes to be sold by March 31 in all retail markets of the country except in the cities of Tokyo and Osaka, which will be opened to them by the end of October. At present, the sale of foreign cigarettes is restricted to a handful of stores in the country.

The new package came amid a government-orchestrated publicity drive designed to avert a protectionist backlash in Washington by attempting to demonstrate Nakasone's determination to improve badly strained relations with the United States, Japan's biggest overseas customer.

In Washington, U.S. Trade Representative William E. Brock welcomed the Japanese moves. "These tariff and non-tariff barriers should lead to improved market access," he said. "But this will be determined in part by the pace and spirit of their implementation."

According to foreign trade analysts here, today's decision reflected a bolder effort by Nakasone than any of his predecessors to muster the political forces needed to break through the wall of interest groups in the bureaucracy, industry and inside his ruling Liberal Democratic Party that has blocked past efforts at trade liberalization.

As part of these efforts, Nakasone today named Chief Cabinet Secretary Masaharu Gotoda to head a task force that will review the red tape involved in meeting product standards and winning licensing approval for imports, which foreign business people consider symbolic of the obscure nature of the Japanese market.

The group is to recommend, by March 31, possible changes in some 30 regulations now governing a wide range of goods, including cosmetics, pharmaceuticals, plywood, processed foods and electrical appliances.

Nakasone has also moved to put more political muscle behind the government's Office of Trade Ombudsman, an ad hoc panel formed early last year to field complaints by foreign business people about market access. That office has so far been largely hamstrung in attempts to field complaints because of stiff resistance by government departments determined to preserve their bureaucratic prerogatives.

Nakasone indicated today he would, at least temporarily, brush aside U.S. demands for the further liberalization in Japan's imports of beef and citrus fruit. The two commodities, which Japan now controls by quota, have represented one of the thorniest issues in troubled two-way trade ties.

U.S. Trade Representative Brock applauded the Nakasone government's promise of a high level review of Japanese testing and certification procedures. Changes that would give foreign goods the same treatment as domestic products "could result in a significant opening of the Japanese market," he said.