TOKYO, SEPT. 27 -- Japan may delay indefinitely development of its next-generation fighter-bomber jet rather than accept what it considers to be one-sided proposals from U.S. aircraft manufacturers for a joint program, according to Japanese officials.

Prime Minister Yasuhiro Nakasone, under pressure from the United States and concerned about growing tension in the alliance, has pledged privately that Japan will not go it alone in developing a plane, as industry and the military here wished. But Japanese officials now say they might abandon the effort entirely or delay it for several years rather than accept proposals that they say do not adequately share profit and technology.

The new complaints may represent, to some extent, a bargaining position as Yuko Kurihara, head of Japan's Self-Defense Agency, leaves Tokyo to meet with his U.S. counterpart, Defense Secretary Caspar W. Weinberger, later this week. But they also demonstrate that the potentially contentious issue, which one official here said could be "ten times more trouble than the Toshiba case," remains unresolved long after both countries hoped the matter would be settled.

In May, Japanese officials announced that Toshiba Machine Co., an affiliate of the giant electronics concern Toshiba Corp., illegally sold the Soviet Union high-tech machine tools that can be used to make submarines nearly silent.

Nakasone and Reagan administration officials have worked hard to strengthen bilateral security ties even as economic relations have deteriorated in recent years. The program to build the new fighter-bomber, dubbed the FSX, has become an emotional issue that officials on both sides of the Pacific fear will cause trade frictions to spill over into the defense area.

Japan intends to spend $6 billion or more over the next 20 years to equip its Air Force with a new jet to support ground troops and warships. Officials and engineers inside the Japanese defense industry and the Self-Defense Agency, Japan's Pentagon, have pushed for a basically Japanese plane, saying the technology exists here and should be encouraged.

Weinberger and other U.S. officials have urged the Japanese to modify an existing U.S. jet in cooperation with a U.S. arms maker, saying that -- as with Israel and its home-grown Lavi fighter -- Japan will not build enough jets to recover the cost of independent development. Israel recently abandoned its efforts to produce its own fighter. Japan, unlike Israel, has a policy of not selling arms abroad, further reducing the market for a Japanese plane.

But the debate between the two countries has moved beyond a dry list of pros and cons to become entangled in bitter feelings about Japan's trade surplus with the United States, the Toshiba Machine Co.'s sale of militarily useful technology to the Soviet Union and the relative efficiency of the two nations' industries.

The American side says that it has three jets already in service -- the F16 made by General Dynamics Corp. and the F15 and F18, made by McDonnell Douglas -- that could be easily modified to suit Japanese requirements. Japan would spend at least $3.5 billion just to develop a new plane from scratch, the Americans say.

But Japanese officials, with frequent references to engineering problems in the B1 bomber and cost overruns in other U.S. weapons, respond that U.S. experience cannot be applied here.

"Japanese industry has an impeccable record of not deviating from the price," one official said. "It is the American companies, rather, that always hike up the cost once development begins."

A consortium of Japanese companies led by Mitsubishi Heavy Industries Ltd. lobbied through the spring for an essentially Japanese plane equipped with U.S.-made engines. But members of Congress led by Sen. John Danforth (R-Mo.), whose state is home to both aircraft manufacturers with a stake in the issue, argued that Japan, given its huge trade surplus with the United States, should import U.S. fighters.

When Weinberger visited in June, Nakasone promised that Japan would not make a "unilateral decision against the wishes of the United States," as one official here paraphrased. The Toshiba Machine Co. case angered Congress and also appeared to strengthen the U.S. hand on the fighter-bomber issue.

"Maybe the trade situation and the Toshiba scandal have contributed to a reassessment of their desire to build one of their own," U.S. Ambassador Mike Mansfield said in an interview several weeks ago.

But a team of Japanese engineers that toured McDonnell Douglas and General Dynamics recently returned without enthusiasm for any of the options.

The F16, with one engine, does not afford Japanese pilots the margin of safety they want for maritime flying, officials said, and General Dynamics did not seem eager to redesign the plane radically. The F15, at more than $40 million per plane, is seen as too expensive.

The F18, developed as a fighter-bomber for use over the ocean, seemed the best bet, the engineers reported. But they complained about McDonnell Douglas' proposed cost to develop a variation for Japanese use -- at about $1.8 billion, according to officials here -- and about the company's reluctance to allow Japanese engineers to change the airframe, the structural framework, to suit their needs.

"None of them fits perfectly," said one official at the defense agency.

An adaptation of the F18, with Mitsubishi acting as prime contractor, still seems the likeliest outcome. But officials here said they are prepared to postpone a decision indefinitely, hoping that general relations improve, or to make do with F4s and F15s, which Japan is already buying for aerial dogfight missions.

"The U.S. companies don't want to risk profit for political reasons," one official here said. "They want to make maximum money out of the deal. . . . My feeling is that the diehards on both sides haven't really changed their feelings."