The sealed grand jury indictment against South Korean businessman Tongsun Park contains detailed information about large amounts of money he paid to members of Congress, The Washington Post has learned.

The investigation of Park has focused on his relations with former members of Congress.

Justice Department officials continued yesterday to refuse comment on the secret indictment filed last week, but are known to feel that the detailed charged is strong enough to support conviction, apparently on some form of the federal bribery statues.

It is not viewed simply as a bargaining tool to put pressure on Park to return to the United States and testify voluntarily about his role in the South Korean government's expensive campaign to lobby Congress, the officials said.

Park's lawyer, William G. Hundley, has said his client is willing to return to London from Seoul to face extradition proceedings on the still unnamed charges.

But Hundley said yesterday that he would recommend that his client refuse to testify voluntarily if he is somehow forced to return to the United States. "The South Koreans would have to kidnap him to turn him over," he said. "There's no way they could legally do it. But if they brought him back, my guess would be he'd take the Fifth (Amendment protection against self-incrimination). Then they'd probably immunize him and force him to testify."

The information that the sealed indictment mentions names of members of Congress and amounts of money raises the possibility that other indictments may soon follow.

Attorney General Griffin B. Bell saidin a Los Angeles Times interview earlier this week that "we're getting into the season (for indictments)."

He noted that "very few" prosecutions were likely, and indicated that former rather than current members of Congress would be the targets. Former Reps. Richard T. Hanna (D-Calif.) and Cornelius Gallagher (D-N.J.), both close friends of Park, have been the target of much grand jury scrutiny in recent months.

Justice Department officials have alluded privately to "high-level diplomatic negotiations" with the South Korean government as an explanation of why the grand jury indictment was timed while Park was visiting South Korea.

Hundley suggested yesterday that the indictment was planned while his client was in Korea because Justice "wants to bypass a lengthy extradition fight" in Britain.