Kansas Gov. Kathleen Sebelius is Barack Obama's choice for secretary of Health and Human Services, a White House source said Saturday. (Charlie Riedel/ Associated Press)

U.S. President Barack Obama has picked Kansas Gov. Kathleen Sebelius to fill the post of secretary of Health and Human Services, more than three weeks after his first choice for the job withdrew, a White House source said Saturday.

Obama will formally announce the nomination on Monday, said the source, who spoke on condition of anonymity.

Sebelius, 60, was an early Obama supporter and her name had been floated for several cabinet posts. She's in the middle of her second term as governor and is legally barred from seeking a third term next year.

The president's first choice for the position, former Democratic senator Tom Daschle, withdrew his nomination Feb. 3 after it was disclosed that he failed to pay more than $120,000 US in taxes. He also faced criticism for close ties with health-care interests, including paid speaking engagements.

Daschle said he withdrew because he would not have been able to operate in the position "with the full faith of Congress and the American people." He also said he didn't want to "be a distraction" from Obama's drive for health-care reform.

Daschle, who comes from South Dakota, was a senior figure in the Obama campaign throughout the lengthy presidential race and recently wrote a book about how to improve health care.

Sebelius drew praise for the consumer watchdog role she played as Kansas insurance commissioner for eight years before she became governor.

She said in December that she had removed herself from consideration from a cabinet post, saying Kansas's budget problems needed her attention.

Many Democrats had hoped Sebelius would finish her term as governor and run for the U.S. Senate, to become the first Democratic senator from Kansas since 1932.

Abortion foes strongly oppose Sebelius because she once had a reception attended by a late-term abortion provider who now faces criminal charges.

Democrats say there was never any doubt that Obama would appoint a secretary of Health and Human Services who supports abortion rights.

With files from the Associated Press