Senate Minority Leader Howard H. Baker Jr. (R-Tenn.) confirmed yesterday he will be a candidate for president in 1980, but said his formal announcement is yet to come.

Baker, interviewed on "Face the Nation" (CBS, WDVM), said flatly that "I am a candidate for the Republican nomination."

But, when asked if that amounted to his announcement, Baker insisted that a formal announcement has become a ritualistic ceremony - and "media event" - over the years, and that he intends to hold such a ritual later.

Baker also said he will retain his post as minority leader of the Senate, although he would allow the assistant Republican leader, Sen Ted Stevens (Alaska), to take over most of his duties. Baker said it is "not the precedent of the Senate" for a member of the leadership to resign while seeking higher office.

Baker's statement was his strongest yet about his presidential ambitions, although he has made no attempt to keep his candidacy a secret.

In an appearance in Manhattan, Kan., on March 8, Baker said he planned to run, but added that "I don't plan to announce here today." And in early April, he announced the appointment of an "exploratory" campaign manager.

Legally, he became a candidate for the Republican nomination on Jan. 31 when a Baker-for-President campaign committee registered with the Federal Election Commission.

On another subject, Baker said he still leans against Senate approval of a new strategic arms limitation treaty with the Soviet Union, but declined to say how he would vote. He said it is still possible he may support SALT II.