The Department of Veterans Affairs will tell Congress today it can have approximately 15,000 hospital beds available for casualties of Operation Desert Storm within 72 hours -- a step that would add a new role to the nation's largest hospital system.

Veterans Affairs Secretary Edward J. Derwinski will seek to assure members of the Senate Appropriations subcommittee on the VA, Housing and Urban Development Department and independent agencies that the 172 veterans hospitals are ready to become the primary backup for the Defense Department's relatively small hospital system. Derwinski is expected to sidestep questions about how many casualties the VA has been told to expect.

Veterans organizations, however, are less certain about the VA's ability to care for Persian Gulf evacuees.

In a soon-to-be-published report, four groups -- the Paralyzed Veterans of America, Disabled American Veterans, Veterans of Foreign Wars and Amvets -- claim staff shortages at many veterans hospitals have been "aggravated by recent budget shortfalls and the call-up of hundreds of military reservists."

The groups also said they doubt that private hospitals can "accommodate the large number of veteran patients that would be displaced by wounded soldiers."

"We could see the potential threat, not only to people in Desert Storm, but in the hospitals now," said John Hanson, an official with the American Legion, the nation's largest veterans group.

VA officials said that no veteran with a service-connected injury who needs immediate medical care will be turned away, but they acknowledge that they will postpone elective surgeries and other care for veterans whose medical needs are not urgent. Some veterans will be moved out of the 80 East Coast hospitals designated as primary care facilties for the war injured, they said.

James W. Holsinger, the VA's chief medical officer and an Army Reserve major general, said VA facilities are certain to be used because of the small number of military hospitals. "They simply don't have the beds," he said.

The Pentagon has "approximately 16,000" beds as compared to 500,000 during World War II, according to the VA.

Holsinger said that, in some special cases, evacuees could begin arriving in the United States within 36 hours of being injured via an "air bridge" of military and commercial jets. The shuttle would carry the wounded out of the Middle East and bring medical supplies to front-line military hospitals.

Acting for the first time under a 1982 law that designates the VA as a backup system for the military hospitals, the VA has promised to have 9,000 beds available within 24 hours and up to 25,000 within 25 days.

"Given the time and resources we have, we're as ready as we can be," said Raymond C. Bonnabeau, director of the VA's office of medical emergency preparedness.

Bonnabeau and Holsinger rejected suggestions that the VA's medical staff, used to treating a population composed largely of elderly men, will need additional resources to deal with combat injuries. "I don't think so," said Bonnabeau. "We're not trying to turn the VA into trauma centers."

The VA is assuming that most of the injured will have been stabilized in the theater hospitals and then be given secondary care at medical facilities in Europe, Bonnabeau said. Most of the injured are not likely to arrive in the United States until a week after they are wounded, Bonnabeau said.

"It could be within a week; it could be longer. It depends on a number of things," including the number of casualties, he said.

The VA's Desert Storm planning operations are run by a staff of 10 people who work out of a windowless basement command center in the VA's Martinsburg, W.Va., hospital, about 70 miles northwest of Washington. It is linked by various "secure" communications channels with all the hospitals and the Pentagon.

The Armed Services Medical Regulating Office, at Scott Air Force Base, Ill., would decide which injured go where, decisions Bonnabeau says would be based on the home towns of the service persons and their types of injuries. "It's DOD policy to place them as close to their home town as possible," Bonnabeau said.

Long plagued by staffing shortages at many of its hospitals, the VA plans to temporarily reassign doctors and others from hospitals in the West to care for the injured.

Hospital directors are being told they can hire temporary doctors and nurses under an "open-ended budget" that will be billed to the Pentagon, Bonnabeau said. "They'll just get what they need to get," he said.

Rep. G.V. "Sonny" Montgomery (D-Miss.), chairman of the House Veterans Affairs Committee, was briefed on the VA's plans and voiced his support last week. "I am confident the VA is ready and capable of delivering prompt, quality care to our armed forces personnel," he said.