House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) has been told that the House committee investigating South Korean influence buying on Capitol Hill has subpoenaed the rental records on the Washington house he lived in for 10 years, a top O'Neill aide said yesterday.

Gary Hymel, the Speaker's executive assistant, said that O'Neill called Rep. John J. Flynt (D-Ga.), chairman of the Committee on Standards of Official Conduct, earlier this week because he had heard rumors about such a subpoena.

Flynt told O'Neill the subpoena was issued because someone had told committee investigators that Tongsun Park, an indicted South Korean lobbyist, had paid O'Neill's rent and "we check everything out," according to Hymel.

Flynt could not be reached for comment yesterday, but other familiar with the investigation cautioned against attaching great significance to such a subpoena.

Hymel said O'Neill called the incident "ridiculous" and added that the Speaker was gathering his canceled rent checks and would make them available if the committee wished.

Charles J. Pitzer, an attorney for the Charles E. Smith Co., which rented the house to O'Neill and Rep. Edward P. Boland (D-Mass.), told reporters yesterday that a subpoena had not yet been received.He added that the committee had asked him to say nothing more.

O'Neilly consistently has denied having had anything more than a passing acquaintance with Park. O'Neill was guest of honor at two elaborate birthday parties sponsored by Park in 1973 and 1974.