The White House Office of Management and Budget has proposed shutting down St. Elizabeths Hospital, the sprawling federal facility for the mentally ill in Southeast Washington, federal and District sources said yesterday.

The OMB proposal, contained in an internal preliminary 1983 budget allocation sent to the U.S. Department of Health and Human Services, is the most drastic step ever suggested for the 126-year-old institution, which has undergone attempts to shift it to the D.C. government but never a threat of total shutdown.

However, officials involved emphasized that any decision as to what should be done with St. Elizabeths is far from final. "Nothing is cast in concrete," said one top HHS official.

St. Elizabeths cares for nearly 2,000 inpatients and more than 3,000 outpatients, most of them D.C. residents.

The city "is not in the position of having adequate psychiatric beds to meet the needs of the District residents," said D.C. Department of Human Services Director James Buford of the OMB proposal. "This without question is the most extreme and drastic action I've heard recommended."

Staff doctors at the hospital raised concerns about the possibility of dangerous and seriously ill psychiatric patients being "out on the streets." One physician characterized the situation as a "sinking ship being torpedoed."

HHS officials in the Reagan administration say they, too, are concerned and are preparing to appeal the OMB proposal, which suggested a "phasing out of federal responsibility" for the hospital next year and would amount to closing it down.

Up to now, HHS has been proceeding on a long-term legislative proposal to transfer control of the hospital to a public corporation with a board appointed by the president.

One source familiar with OMB-HHS negotiations contended that the shutdown proposal is more a "negotiating tactic" than a serious intent to do so. He said that White House officials have been asking, "Why isn't the District running its own hospital?" and that the "hard line" proposal was intended to "shake up the troops" with the goal of improving hospital managmeent and lowering the overall federal expenditures.

One HHS official conceded that it might be a "situation where OMB comes up with something very dramatic to get our attention," but that "the administration has the horsepower to in fact make something happen if they want to give it priority."

He said that whatever the eventual outcome, the administration is "very serious about a change in the status" of St. Elizabeths and the way mental health services are provided in the District.

"We're carrying on a professional conversation to explore all avenues and to come up with the best possible solution for what everyone agrees is not an ideal situation," said another HHS source.

He listed these arguments raised by HHS as to why shutting down the hospital is not a "workable" proposal:

It would require legislation to do it and it is doubtful that Congress would approve.

It would "probably put us in contempt" of the court-ordered long-term effort to place about one-fourth of institutionalized patients in less restrictive community facilities by 1986.

There are not presently available alternative facilities to house all the patients.

D.C. budget director Gladys Mack also stressed that the hospital and its patients are a federal responsibility. "The District does not have a substitute facility nor do we have $100 million we could use to make up for the loss of federal funds."

St. Elizabeths Hospital operates on an annual budget of about $120 million, with about $100 million of that provided by the federal government and the rest reimbursed by the District and other sources.

Details, if any, on the proposed closedown or phasedown of the hospital were not available yesterday. OMB officials declined to speak with reporters and spokesman Edwin L. Dale Jr. said he was "not going to say anything."

Alternatives to the shutdown proposal that may be considered in coming OMB-HHS discussions, noted one HHS official, include contracting out the hospital to a private firm, forming a public corporation but including it as part of the District's budget or otherwise increasing the District's financial responsiblity.