The U.S. Senate has postponed confirmation hearings for three nominees to serve in President-elect Donald Trump's Cabinet, all wealthy people with wide-ranging potential conflicts of interest, including billionaire Wilbur Ross for Commerce secretary.

The Senate Commerce Committee said on Tuesday it was moving Ross's hearing to Jan. 18 from Jan. 12 because Ross has not completed all of the necessary government paperwork.

Trump takes office on Jan. 20.

"While Mr. Ross has submitted his responses to the committee's questionnaire, we have not yet received the ethics agreement he is working on with the Office of Government Ethics and the Department of Commerce to finalize," the panel's Republican and Democratic leaders said in a joint statement.

The Ross delay came shortly after postponements of hearings for Trump's choices to head the Education and Labor departments.

The Senate Health, Education, Labor and Pensions Committee delayed a hearing for Betsy DeVos, the billionaire Republican donor tapped for Education secretary, to Jan. 17 from Jan. 11.

The committee's Republican majority said on Twitter on Monday that it had moved DeVos's hearing at the request of Senate leadership to accommodate its schedule.

DeVos is a former chair of the Michigan Republican Party and an advocate for the privatization of education.

The same panel had tentatively slated a confirmation hearing for fast-food executive Andy Puzder, Trump's selection for Labor secretary, for Jan. 17. With DeVos's hearing moved to that date, the committee said it had no specific date selected for Puzder's hearing and may not hold it until February.

Puzder has submitted his paperwork to the Office of Government Ethics, according to a Trump transition staffer.

Puzder is chief executive of CKE Restaurants Inc , which runs the Carl's Jr. and Hardee's fast-food chains. He has been a critic of government regulation of the workplace and the National Labor Relations Board.