In a move the White House quickly dismissed as unnecessary, two top Republican congressional leaders called on President Carter yesterday to appoint a Watergate-type special prosecutor to investigate the Korean Central Intelligence Agency's attempts to influence U.S. officials.

Sen. Howard Baker (R-Tenn.), the Senate minority leader, said at a press conference that "fairness and equity" demand that the Democratic administration pursue charges of South Korean influence-buying just as Republicans pursued the Watergate investigations that eventually toppled President Nixon.

The Justice Department has been investigating allegations that the South Korean government spent hundreds of thousands of dollars in cash, gifts and entertainment on U.S. officials to ensure continued support for President Park Chung Hee's regime in Seoul.The inquiry has been going on for more than a year without returning any indictments.

Two House committees are conducting separate investigations of the charges.

Baker was careful to say he was not suggesting the South Korean scandal was a Democratic Watergate. "I hope it isn't," he said. "But I do think the issue is important enough to deserve a full impartial investigation."

Baker and Rep. John Rhodes (R-Ariz.), who said he agreed with his colleague's suggestion, were vague in explaining why a special prosecutor was needed. Both cited Justice Department leaks to newspapers as one reason, but they could not offer specifics of such leaks.

White House press secretary Jody Powell responded immediately and negatively to the GOP demand, saying a special prosecutor was unnecessary because the Justice Department already was pursuing the matter vigorously.

He described the Baker-Rhodes press conference as a "fairly adept two steps," and added that he had "no desire to add to the attention he [Baker] would hope to attract."

A Justice Department spokesman said later that several other members of Congress have written Attorney General Griffin B. Bell, suggesting appointment of a special prosecutor in the case. In each instance, Bell has replied that the department's public integrity section was pursuing all leads thoroughly without a time limit for completing the inquiry, the spokesman said.

In a related matter, the House ethics committee called an emergency closed meeting yesterday to discuss how to tighten procedures for controlling the confidentially of sensitive information.

The unscheduled meeting was called after the Washington Post reported yesterday that the committee had voted in executive session to subpoena four executive branch officials who might have had access to secret intelligence reports naming congressmen who took money from South Koreans.

Several members expressed concern about the story because the committee is in the midst of negotiating with the CIA and the National Security Agency for delivery of classified documents.