West German Chancellor Helmut Schmidt yesterday defended his plan for a European monetary system and strongly implied that he has won Japanese aproval of the plan.

Schmidt said the plan, of which he is a principal airchitect, would not create negative effects for the Japanese yen or the American dollar and said that Prime Minster Takeo Fukuda has expressed a "positive" attitude on the issue.

Schmidt, after two days of meetings with Fukuda, briefed reporters on the results of conference designed to cement a growing friendship between the two economic superpowers.

His comments on the European currency system were a mild surprise because the Japanese previously had expressed concern that creation of a separate money system in Europe would be taken as a vote of no confidence in the dollar.

Since the Japanese conduct most of their foreign trading in dollars, any threat to its value arouses fears here. But Schmidt stressed his position that the yen and the dollar would not be adversely affected.

"I did inform the Prime Minister about plans for a European monetary association and the Prime Minister stated that his government takes a positive position and attaches positive expectations to the endeavors in that field," he said.

Asked at the news conference if his plan was designed as a defense against a declining dollar which would drag the yen down along with it. Schmidt expressed a hasty denial: "the answer is no," he said.

He said the plan would serve only to stabilize currencies used in trade among European nations and said it would have "no consequences for the parties of the dollar or the yen. It is an understanding directed against nobody . . ."

In an aside obviously directed at the U.S. however, he said the plan "may supply the rest of the world with some incentive to bring about stable rates for their currencies as well."

As Schmidt spoke the dollar was taking another nosedive on the Tokyo foreign exchange, falling below 185 yen for the first time in two months.

The latest decline was attributed to remarks made in Saarbruecken, West Germany by U.S. Energy Secretary James Schlesinger, who said he does not expect American oil imports to decline to six million barrels a day by 1985, a promise made at the Bonn summit by President Carter.

Schmidt also made a point of praising his country and Japan for moving rapidly to keep the promises they made at the Bonn Summit leaving the impression that he does not think the U.S. has moved fast enough.

By Schmidt's account, the sessions with Fukuda have been unqualified successes and his summaries underscored the close and friendly relationship which has been built up between the two countries in the past two years. He praised Fukuda effusively, referring to the "clarity" of his judgement, and said the talks had been conducted in an excellent atmosphere.

He went out of his way to praise Japan's current economic performance. While Fukuda had promised a 7 per cent growth rate in this fiscal year, Schmidt said it would be an "enormous achievement" in these times if it reached even five or six per cent.

Schmidt also said he supports the plan to hold the next economic summit meeting in Tokyo next June, an event which is important to Fukuda who seeks additional prestige by playing a role in international economic affairs.