The Senate Veterans' Affairs Committee has rejected the administration's plan for drug testing of nearly 194,000 Veterans Administration employes, an action that a senator said undercuts a presidential plan for testing federal workers in sensitive jobs.

Although the committee vote is subject to action by the full Senate, Sen. Dennis DeConcini (D-Ariz.), who last June worked out a compromise drug-testing plan with the administration, was furious yesterday that the administration failed to fight the move and expressed doubt that he would lead a fight to overturn it on the floor.

"I feel a little betrayed," DeConcini said. "They didn't do anything for me.

"I want to reassess how much of their water I want to carry," he said, describing the action as "the worst" possible setback to the testing plan.

The senator said he knew of no other agency that Congress is moving to exempt from the president's Sept. 15 executive order.

A Justice Department official, speaking for the administration, noted last night that the measure "is at odds with the agreement" the administration reached with the Congress earlier this summer over drug testing and said the administration expected the provision would be dropped when it is brought before the Senate. The spokesman had no comment on DeConcini's anger at the lack of Republican support in the committee.

A VA spokesman confirmed that the agency did not take a position on the issue when it came before the Senate committee Friday.

The panel's 8-to-3 vote came after Sen. Alan Cranston (D-Calif.) complained that the Reagan plan for annual testing would cost the VA "at least $3 million" and would accomplish little.

Cranston, chairman of the panel, was joined by Sen. Frank H. Murkowski (R-Alaska), the committee's ranking minority member, in sponsoring a provision blocking the testing in a veterans compensation bill.

"We believe that it has not been demonstrated that a mass-drug-testing program of VA health-care employes is necessary or would be cost effective as a means to reduce drug use among such employes," said Cranston. "There is no evidence I am aware of to suggest that VA health personnel generally have any particular drug abuse problems."

DeConcini attempted to strike that provision but he could muster only the votes of two Democrats, Sens. George J. Mitchell of Maine and John D. Rockefeller IV of West Virginia. The opposition included some of the Senate's leading Republican conservatives, Sens. Strom Thurmond of South Carolina and Alan K. Simpson of Wyoming, and surprised DeConcini, who earlier this summer pushed for a compromise package on federal worker drug testing that was signed into law by the president.

The language approved by the committee Friday would effectively bar the VA, one of the first agencies moving to implement the testing plan, from conducting any random tests. It would allow individual tests in cases in which officials have "reasonable suspicion" that an employe may be using illicit drugs, was involved in an accident or was in a rehabilitation program.

VA spokesman John Scholzen said the agency, which employs about 220,000 workers at its 172 hospitals and medical facilities, had determined that almost 200,000 of them could be subject to testing under the Reagan plan. It called for testing of employes in "sensitive" positions and specifically called for testing public health workers.

Congress delayed implementation of the president's plan for most agencies earlier this summer until the Department of Health and Human Services could develop technical guidelines for the testing. Entities that had begun testing, such as the military and the Department of Transportation, were allowed to continue their tests.

Scholzen said the VA was awaiting guidelines before moving ahead with its testing.

A spokesman for Rep. Steny H. Hoyer (D-Md.), who has opposed all testing of federal workers as unconstitutional, said Hoyer would support the VA ban in the House. Earlier this summer, Hoyer won a House vote supporting his position but, faced with Senate opposition, joined with DeConcini in reaching a compromise with the administration that requires the HHS guidelines before most testing can proceed.