It was vintage Tongsun Park in his favorite setting.

There was delicious food and good wine in an elegant ambience, his home in the suburbs of Seoul, and an attentive audience to head his monologue version of why it all happened.

What he had done, he said, he had done for his country, and there were no regrets.

Always, he said he was striving to preserve and protect "the relationship," words he spoke in a soft, reverent tone to denote the alliance between the United States and South Korea.

No one ever suggested he said, that he might be breaking American. People must understand, he said, that lobbying is an important part of the American system of government, and they shouldn't frown on it.

The words of his indictment say he did what he did as a paid agent of the Korean Central Intelligence Agency. No, said Park, it wasn't like that at all. Sometimes his plans in Washington happened to coincide with those of his government, but he was, he insisted, acting essentially alone in his dealings with congressmen.

Park, the 42-year-old former playboy and lobbyist, unfolded this version of his career tonight at a dinner he gave for American reporters in his home on the outskirts of Seoul.

His days here are occupied by hours of questioning by Justice Department lawyers operating under a U.S.-Korean agreement to delve into the congressional influence-buying scandal of which he is a central figure. He is said to have doled out several hundred thousand dollars in cash to some congressmen in hopes that they would support Korea's cause in Congress.

By the accounts that have leaked out, Park has talked freely about large payments to five congressmen. He has not yet testified about whether he did it on government orders, as the 36-count indictment alleges.

As his servants ladled out course after course of Korean food. Park delivered his version in a soft-toned monologue, sometimes seeking sympathy, but always making it clear that he feels no remorse. He declined to answer questions about the substance of the case agai nst him. His Washington lawyer, William Hundley, sat nearby to referee the questions and decide what was in or out of bounds.

Park said the interrogation under way in Seoul is not he ordeal it started out to be. He has become rather fond of the two Justice Department lawyers who lead him through the record each day. They seem to know the case pretty well, he conceded. He doesn't even mind the FBI agent who gives him polygraph tests, but he does object to the strap they wrap too tightly about his forearm when the tests are administered.

It seemed that in Park's mind the bad guys are back in Washington. He remembers the social leaders there who resented his success at party-giving and social-climbing and who thought that any young Oriental who has so much money and who rose so fast must be working for some suspicious organization.

There were the bureaucrats in the South Korean government who didn't like him. They thought he was too liberal, he said, and there is an implication in his words that some former government figures who testified about him did so out of spite.

There were reporters in Washington who, in their zeal to get him, stepped over the boundary line of propriety, he claimed. He cited, with a special distaste, Maxine Cheshire of The Washington Post.

THere are the hyprocrites, too, he said, who are forever talking of all that foreign aid being wasted on a country like Korea. Americans didn't give that aid out of generosity but out of self-interest, to protect their own interests in Asia, he asid.

Americans don't understand that lobbying is a normal part of the workings of democracy, he said. When large organizations do it in Washington, he said, no one raises any questions. They only get upset, he said, when ona person alone goes about trying to sway Congress.

Did anyone ever suggest to him that the way he was going about it was against the law? a reporter asked. Never, said Park.

Far from regretting the past, Park said he believes he was a success in Washington in a classic American way. An unknown Korean. he had achieved prominence in a strange city and had helped his country in the process.

The hardest part, he said, is the impact on his mother who was heart-broken at seeing her son described as a "swindler" in a news magazine.

With the desert and coffee, Park introduced a young Korean folksinger who sang and played the guitar. As the evening ended, he passed out gifts - a calendar, dessert spoons and forks, and a record - to the guest. Just before they left, Park joined the folksinger in a final song, a Korean number called, "Farewell."