The White House abruptly postponed its plans to nominate a new administrator for the Veterans Administration yesterday after key members of the Senate Veterans' Affairs Committee complained that they had not been consulted about President Reagan's choice.

But sources at the White House said the president still plans to nominate Harry N. Walters, an assistant secretary of the Army, within a few weeks, after congressional feathers are smoothed.

Walters was to be nominated by the White House at noon yesterday and formally introduced to representatives of the nation's major veterans' organizations later in the day.

But the announcement and ceremony were canceled after the White House received telephone calls from Sens. Alan K. Simpson (R-Wyo.), chairman of the Veterans' Affairs Committee, and Strom Thurmond (R-S.C.), a committee member and one-time critic of Walters.

Any VA nominee would appear before Simpson's committee before he could be confirmed by the Senate; Simpson was described by sources as being "vitriolic" in his conversation with the White House yesterday. The announcement of Walters' nomination was postponed one hour after the White House received Simpson's call, a source said.

James O. Ratliff, an aide to the senator, said Simpson was upset because the White House had not discussed its choice with committee members and had not interviewed Simpson's candidate for the job, Thomas E. Harvey, a heavily decorated Vietnam veteran and the current staff director of the Senate Veterans' Affairs Committee.

In a statement yesterday by his office, Simpson, who was in Wyoming, said the White House should at least have given Harvey the "common courtesy of an interview, especially since he was not only recommended by me but several other senators."

Harvey, whom Simpson nominated several weeks ago, was hastily called to the White House yesterday for an interview after Simpson complained. Thurmond, meanwhile, declined to comment about his role in the incident, but sources said he complained at Simpson's request.

Deputy White House press secretary Larry Speakes declined to comment about yesterday's snafu. But administration sources said the White House hasn't changed its mind about Walters, a former all-American football player, West Point graduate and New York businessman.

Yesterday's flap is the latest in a series of embarrassments for the administration over its choices for VA administrator.

It took Reagan four months to pick Robert P. Nimmo to head the government's third-largest agency. Nimmo resigned in October after 16 turbulent months marred by criticism that he was unsympathetic to the needs of Vietnam veterans and charges that he had violated the law by using a government chauffeur for his personal use.

Simpson said yesterday that he did not plan to block Walters' nomination in the Senate, but he indicated that he would have to know much more about him before approving his nomination, if it is forthcoming. Walters, currently assistant secretary of the Army for manpower and reserve affairs, could not be reached for comment.

Walters, 46, is no stranger to Senate scrutiny. At his confirmation hearings last year for his current post, he was criticized by Thurmond for spending only four years in the Army after being graduated from West Point in 1959. Walters said he left the military because he had a family to support.

Veterans' leaders, who earlier had expressed the hope that Reagan would nominate a Vietnam veteran to head the VA, expressed cautious optimism yesterday about Walters, who did not serve in Vietnam. If nominated and confirmed, Walters would be the first VA administrator who never served in combat.

Mylio Kraja of the American Legion said he was impressed with Walters' business skills. Walters turned a failing paper company in Potsdam, N.Y., into a profitable venture shortly before moving to the Pentagon.

But John Terzano of the Vietnam Veterans of America called Walters "another uninspired choice" and said he "will simply be another administrator who had to get on-the-job training." graphics /photo: HARRY N. WALTERS ...was to have been named yesterday