Although the South Korean government has officially closed the book on the Blue House bugging incident, a number of voices are continuing to demand that the United States be forced to explain what really happened.

The Foreign Ministry said Monday in a roundabout way that it accepted the U.S. ambassador's denial that there had once been a bug in the Blue House, President Park Chung Hee's official residence.

But some newspapers and the weak opposition New Democratic Party declared that the incident should not be closed until the United States offers a clarification.

The party chairman, Lee Chul Seung, said he did not believe the denial, and insisted that a more influential, American, such as President Carter, should offer an explanation.

Lee said in an interview that he tended to believe the word of former ambassador William Porter that the United States ahd bugged the Blue House sometime before he arrived in 1967.

The denial of Porter's version on Monday by Ambassador Richard Sneider "will never satisfy the feelings of the Korean people," he added. Porter said Monday that he did not actually know if there was bugging before his arrival in Seoul, only that he had been told there was.

Porter's earlier comments, made in a television interview, triggered a week of anti-American demonstrations in Seoul.

Meanwhile U.S. officials said they believed the Seoul government tolerated demonstrations to vent its frustrations about a long series of U.S. rebuffs and humiliations, most of them growing out of the Tongsun Park affair.

Letting the demonstrations continue, they said, was also a way of pressuring for a written U.S. denial. That in itself, they said, was evidence that President Park's government was feeling an unusual amount of public pressure to stand up to the United States.

"It was triggered by a long chain of events in which we were seen to be pushing them around and being insensitive to their national sovereignty," one official said."It is what Koreans call 'big-power chauvinism.'"

Among those incidents, he added, was the government's reluctant decision to make Tongsun Park available for questioning in the United States. Another is the pressure to make available for questioning South Korea's former ambassador to Washington, Kim Dong Jo, who also has been implicated in the lobbying scandal.

In both instances, the government at first appeared adamant against cooperating with U.S. officials. There was a burst of public anger, still expressed privately by government officials, when the U.S. investigators required Park to come into the U.S. Embassy here to sign papers concerning his questioning.

The government seemed to come around to a more cooperative position only when threatened with a loss of the $800 million in military equipment promised as compensation for the impending withdrawal of U.S. troops.

Coming on top of those incidents, the U.S. officials said, the reported bugging triggered anti-U.S. demonstrations and provoked the government into allowing them to continue.

According to the embassy's analysis, some of those protests may have been spontaneous but others were not. The government, which does not permit street demonstrations, decided not to bottle them up until a written denial was extracted, the U.S. officials assume.

Seoul's newspapers, which often reflect a government line, also had a field day comparing the immorality of the alleged bugging to the accusations of immoral lobbying lodged against Tongsun Park and other Koreans.

The lobbying investigation, said the government-owned Korea Herald, was supposedly "intended to uphold the integrity and morality of American politics. If American politics should endorse such as immoral act as spying on the presidential office of a friendly nation, it would amount to telling the world that U.S. morality has two faces."

According to news accounts Monday, Foreign Minister Park Tong Jin told a group of government and ruling-party leaders that the U.S. denial had closed the issue of the alleged bugging.

Lee, the opposition party chairman, indicated, that he intends to pursue the matter within the National Assembly. The New Democratic Party usually supports the government on important issues but occasionally ventures to stake out its own positions.

Sneider's denial, he said, "is not good enough. At least we should have an apology for the bugging and assurances that it will never happen again.

"Suppose that Tongsun Park and Kim Dong Jo would just deny doing anything wrong," he added. "Would that have been enough to satify the United States?"