Secret U.S. diplomatic cables reporting South Korean CIA involvement in a controversial Tokyo kidnaping have been turned over to Japanese reporters in Washington through what State Department sources call clerical error.

The Japanese news service Kyodo made a blanket request under the Freedom of Information Act for documents dealing with the abduction in August 1973 of South Korean opposition leader Kim Dae Jung. The kidnaping has long been thought to be the work of the Korean CIA, but this had never been officially confirmed.

The Kyodo request, lodged in February 1978, required long hours of sifting through documents. To get the work done, the State Department called out of retirement Francis Underhill Jr., former deputy chief of mission at the U.S. Embassy in Seoul and former ambassador to Malaysia.

Underhill said be carefully rummaged through about 250 cables and communications on the affair, approving some of them for declassification and release and holding back others for retention on security grounds. Then he sent the two groups of papers to the State Department's Foreign Affairs Document and Research Center to be processed.

An employee of the documents center, according to State Department officials, mistakenly declassified some of the documents which should have been retained. One of the most serious was a secret cable from then ambassador Philip C. Habib saying the reports of KCIA involvement are 'essentially correct." A confidential cable from Ambassador Richard Sneider quoted then foreign minister Kim Dong Jo as saying a Korean CIA agent was "responsible" for the controvensial kidnaping, and added that the minister "asked that this information be held closely."

Kyodo's report of the declassified papers caused a furor in Japan. State Department employe his been reprimanded because of the incident, and new inquiry into the clearical error is under way.