Japan, seeking to avert a protectionist backlash in the United States and Europe, unveiled today a new series of steps to reduce its trade barriers and open its markets more widely to foreign goods.

The trade package, the second in five months, comes one week before the Versailles economic summit where Prime Minister Zenko Suzuki hopes to ease some of the rancor Japan's booming trade surpluses have aroused.

The new trade plan calls for easing or eliminating import duties on 215 product categories, enlarging quotas for farm and fisheries imports, further streamlining customs, product standards and market distribution procedures, boosting imports of American tobacco, liberalizing trade in services and promoting trade and international cooperation in advanced technology.

The Japanese cabinet formally adopted the package at a special meeting Friday morning--Japan time--shortly after Suzuki issued a rare appeal to the Japanese people to help open markets to more imports on a grass-roots basis. Although he asserted that the persistent perception of Japan as a closed market frequently resulted from "misunderstandings" abroad, he called on the Japanese to be more "forthcoming" in welcoming foreign manufactured goods and investments without discrimination.

The measures follow strong warnings by the United States and Europe that Japan must move quickly to open its markets or face protectionist action. In 1981, Japan's trade surplus with the United States alone hit a record $18 billion and could go as high as $25 billion this year, U.S. officials have predicted.

In January, Suzuki's cabinet ordered the immediate easing or elimination of 67 so-called nontariff trade barriers from a list of 99 specific complaints by major trading partners. Officials said today they had since acted on another 18 complaints.

The first round of measures, however, has failed to appease critics abroad who have called for more dramatic action. Action on the second package was delayed by powerful Japanese farm lobby groups.

Officials acknowledged that it remained unclear to what, if any, extent the second package might help significantly reduce Japan's trade surpluses.

Hiromu Fukada, the foreign ministry's director general for economic affairs, told reporters, "It was the best we could do under difficult domestic circumstances."

While vaguely worded in parts, the 11-page announcement today contained what the Japanese suggested were the most sweeping gestures they would be able or willing to offer for some time to come. It called for:

* Completely eliminating tariffs on 96 industrial products such as machine tools, watches and refrigerators from next April. Import duties are also set to be reduced on 119 other items, including 17 agricultural products. Among them are peanut butter, chocolates, photographic film, nuclear reactors and fountain pens.

* Expanding import quotas on four of Japan's 22 protected farm and fisheries products--herring, preserved pork, hi-test molasses and canned pineapple.

* Moving to increase tobacco imports by ultimately allowing retail outlets to sell foreign cigarettes.

* Ensuring that foreign banks, insurance and securities firms in Japan are accorded the same treatment as their Japanese counterparts.