The White House is expected to nominate Daniel Oliver, U.S. Agriculture Department general counsel, and Kenneth Elzinga, a University of Virginia economics professor, to fill two vacancies on the Federal Trade Commission, congressional and agency sources said.

Oliver, a Republican, would be nominated to succeed James C. Miller III as chairman of the commission, after Miller receives Senate confirmation as director of the Office of Management and Budget.

Miller's confirmation is expected any day.

Elzinga, an independent, would be nominated to replace former commissioner George W. Douglas, a conservative Democrat who resigned last month to return to Texas.

FTC rules require that no more than three of the five commissioners be from the same party. If Oliver and Elzinga become commissioners, the FTC would have three Republicans and two independents.

The sources said that the White House is close to nominating the two, but may have background checks to complete.

Neither Oliver nor Elzinga would be expected to change the FTC's course from the deregulatory, free-market orientation established by Miller.

Oliver, who could not be reached yesterday, also served in the legal department at the Department of Education, is a former executive editor of the National Review magazine, and former director of the American Conservative Union Inc.

Elzinga, 44, is an antitrust expert who writes mystery novels on the side.

He served in 1970 and 1971 as special economic adviser to the assistant attorney general for antitrust, Richard W. McLaren, and from 1971 to 1979 as a member of the Nuclear Regulatory Commission's licensing and safety board panel.

Elzinga, a member of the University of Virginia's faculty since 1967, said yesterday that he has not actively sought a commission seat, but, "I understand I'm being considered."

He has published articles such as "The goals of antitrust: Other than competition and efficiency, what else counts?"

His economic expertise is in the area of industrial organization and public policy, which includes regulation of industry and antitrust policy. Elzinga, a teetotaler, also is known as an expert on brewing industry matters.

Although the administration is said to be close to a decision, other names mentioned as contendors have included the FTC's three bureau directors, Carol T. Crawford, Timothy Muris and Wendy Lee Gramm, and Al Sikes, a Missouri attorney and former colleague of Sen. John Danforth (R.-Mo.), chairman of the Senate Commerce Committee.