A South Korean exile's testimony in Washington yesterday has renewed the controversy here over the 1973 kidnapping of Korean opposition leader Kim Dae Jung from a Tokyo hotel.

Former Korean Central Intelligence Agency director Kim Hyung Wook told the House Subcommittee on International Organizations that Japanese police were aware that KCIA agents were following the Korean politician, but did little to prevent the kidnapping.

The charges could seriously embarrass the Japanese government and revive a diplomatic row with South Korea.

Prime Minister Takoe Fukuda maintained that the government's position on the kidnapping was unchanged, but the opposition Socialist and Communist parties called for an immediate review. Saying there was clear proof that South Korea had violated Japan's sovereignty, they called for Kim Dae Jung's return to Japan from South Korea, where he is currently serving a five-year prison term for antigovernment activities.

The Japan Socialist Party, traditionally hostile to the government of South Korean President Park Chung Hee, called for suspending economic aid to South Korea. The leftist opposition does not have enough strength in Parliament to bring about such a change in policy.

In an open letter to Prime Minister Fukuda, Socialist chairman Tomomi Narita accused the conservative ruling party of conspiring with the South Korean government to hush the case up.

He attacked allegedly corrupt business and political ties between the two countries and called for a radical shift in Japanese policies leading to normalization of relations with North Korea and peaceful reunification of the Korean Peninsula.

Kim Dae Jung, a former presidential candidate, disappeared from a Tokyo hotel room and turned up five days later, dazed and bruised, outside his Seoul home. Widespread suspicion that KCIA agents had engaged in a flagrant violation of Japanese sovereignty led to a bitter breach in Japan's relations with the government in Seoul.

Difference were eventually patched up under a mutually face-saving formula. The Japanese government declared that there was insufficient evidence of official South Korean involvement and that if any ever emerged the diplomatic settlement would be reviewed.

In Washington yesterday, former KCIA director Kim directly challenged the underlying premise for the political settlement with his testimony that the kidnapping was a clandestin operation ordered and executed by the KCIA.

Japan is politically divided over the two-Koreas dilemma, and the kidnapping of Kim Dae Jung, the major opposition figure in South Korea, triggered an uproar when it occurred. Today, once agin, it was the top item on the broadcast news and led the front page of every national newspaper.

Attention centered on the former KCIA chief's explosive allegation that Tokyo police were aware of KCIA surveillance of Kim Dae Jung, photographed three of the agents tailing him and officially warned a South Korean diplomat against any aggressive act. The police issued angry and emphatic denials:

"We never took pictures, nor did we warn the South Korean embassy," said a police spokesman. "We cannot understand why Kim said such a thing in America."

Foreign Ministry sources said they had to accept national police assurances that the allegations are "entirely groundless." While reserving final comment until they have read the full transcript, Japanese diplomats believe that Kim's testimony will not force review of the diplomatic settlement with South Korea. Little of what he said was new, they said, adding that it was based largely on hear-say and lacked clear supporting evidence.

Kim Dae Jung went into exile when President Park declared martial law in South Korea in late 1972. Japanese police said today that they learned of his arrival here in July 1973, but were unable to locate and protect him because he gave false information to immigration authorities. Fearing an assassination attempt, the former presidential candidate was traveling under false Japanese names and changed hotels every two or three days.

Another self-exiled South Korean dissident, journalist Chung Kyung Mo, said: "We think that what Kim said in Washington is essentially correct. We assigned several bodyguards to Mr. Kim [Dae Jung] because we knew of the KCIA moves against him. So we assume the Japanese did, too."

Tokuma Utsunomiya, an independent member of Parliament who specializes in Korean affairs, called for a full inquiry: "The japanese police did not protect Mr. Kim although they knew there was some danger. The government did not make efforts to clarify things. They must do so now."

The South Korean government, which has sought to discredit the former KCIA chief as a turncoat, today angrily denounced him as "a traitor . . . who has angered and disgusted the Korean people." While describing Kim Hyung Wook as an unscrupulous, shallow and ignorant informant, a statement by Information Ministry spokesman Hwang Sun Pil did not specifically deny the charges the former KCIA director made against the Park government.

The accommodation reached between Japan and South Korea was generally seen as a flimsy, cosmetic device because KCIA responsibility for the kidnaping was virtually proved by the Japanese police. In Kim Dae Jung's hotel room they found the fingerprints of an official of the South Korean embassy in Tokyo. The Seoul government claimed diplomatic immunity for first secretary Kim Dong Woon and refused to allow questioning by Japanese investigators.

The South Korean government never admitted guilt, but the implicated first secretary and the head of the KCIA at that time, Lee Hu Rak, were dismissed, and South Korean Premier Kim Jong Pil traveled to Tokyo to offer apologies.

The South Koreans guaranteed that there would be no recurrence of the kidnaping incident and promised to treat Kim Dae Jung like any ordinary South Korean citizen.

The opposition leader, who narrowly lost the 1971 presidential election to Park and was injured in a suspicious road accident, is now in jail. After his forcible return to Seoul he was kept under house arrest for 70 days and was not permitted to take up a visiting fellowship at Harvard's East Asian Research Center. Later he was convicted of campaign violations in the 1967 and 1971 presidential elections. In March of last year he was arrested and sentenced to five years in prison for signing a democracy manifesto.