After weeks of rumors and speculation, White House officials confirmed yesterday that Kenneth M. Curtis is leaving his post as chairman of the Democratic National Committee.

Presidential press secretary Jody Powell said Curtis met with President Carter Oct. 13 and told Carter he wanted to leave the DNC post and return to his home in Maine.

But Powell emphatically denied suggestions that the President and his top assistants were dissatisfied with Curtis or that the former Maine governor was being forced out of the party chairmanship.

"Unnamed sources" who have made such suggestions, Powell said, "are decidedly out of step with the President's views about the man both personally and professionally."

Curtis was not available for comment. He has scheduled a news conference at the DNC thios morning.

Despite Powell's disclaimer, there has been strong dissatisfaction, centered in the office of White House political adviser Hamilton Jordan, over Curtis' performance at the DNC. The mild-mannered Curtis was criticized as a weak leader who exercised too little control over the party machinery and was unable to translate White House wishes into party actions.

The known unhappiness of some in the White House with Curtis fueled the rumors and speculations that he was about to leave the DNC. But these were denied by top White House officials even after Curtis' Oct. 13 meeting with the President.

It was not clear yesterday when Curtis will give up his party post. Powell said the White House would like to name a successor "early next year" but has not made a decision on who it will be.

Several names already have surfaced. They include California National Committeeman Chuck Manatt, former DNC executive director Robert Keefe and Michigan Democratic chairman Morley Winograd.

Democratic sources have suggested in the past that the White House wanted the new party chief to be, like Curtis, an early supporter of Carter in the 1976 primaries, a requirement that would limit the potential choices. Powell said yesterday he knew "of no such prerequisite" in choosing a new chairman.

Powell said that when Curtis met with the President Oct. 13 Carter "expressed regret" and asked him to remain in his post until a successor could be named. He said Curtis agreed to do that.

Powell also said he knew of no plans to offer Curtis a position in the Carter administration.

At the DNC yesterday, according to Curtis associates, there was an "emotional staff meeting" that included tears by some staff members after the White House announcement. But staffers would not discuss the developments until after Curtis holds his news conference today.

In another development, DNC executive director Paul Sullivan said as many as 15 members of the DNC staff will lose their jobs after the first of the year in a reorganization of party headquarters. Sullivan said the reorganization, which he and Curtis initiated, was approved by the White House and that the firms, together with attrition, will cut the fulltime DNC staff from 89 to 65 to 70.