WASHINGTON  Elizabeth Warren, who conceived of the Consumer Financial Protection Bureau, will oversee its establishment as an assistant to President Obama, an official briefed on the decision said Wednesday evening.

The decision, which Mr. Obama is to announce this week, would allow Ms. Warren, a Harvard law professor, to effectively run the new agency without having to go through a potentially contentious confirmation battle in the Senate. The creation of the bureau is a centerpiece of the Wall Street financial overhaul that Mr. Obama signed in July.

Ms. Warren will be named an assistant to the president, a designation that is held by senior White House staff members, including Rahm Emanuel, the chief of staff. She will also be a special adviser to the Treasury secretary, Timothy F. Geithner, and report jointly to Mr. Obama and Mr. Geithner. The financial regulation law delegated to the Treasury Department the powers of the bureau until a permanent director was appointed and confirmed by the Senate to a five-year term.

The decision does not preclude the possibility that Ms. Warren could eventually be named director, and at the least, she would play a pivotal role in deciding whom to appoint to the job, according to the official, who spoke on the condition of anonymity so as not to pre-empt the formal announcement. Several organizations, including ABC, reported the news of Ms. Warren’s impending appointment on Wednesday.