The Reagan administration has asked Congress to boost by 50 percent AIDS research funds in the 1986 budget, but public-health officials testified yesterday that the additional $37.8 million would hardly begin to halt the epidemic.

"AIDS is a natural disaster," said Dr. Michael S. Gottlieb, a UCLA immunologist. "The long-term consequences of this epidemic are as significant as a drought or famine. It will continue to erode the resources of this nation if we do not respond effectively."

Rep. Henry A. Waxman (D-Calif.), chairman of a subcommittee on health and the environment, threatened 10 days ago to subpoena Health and Human Services Secretary Margaret M. Heckler to find out the administration's plans to combat AIDS.

Dr. James O. Mason, acting assistant secretary for health, said that although "no stone has been left unturned," Public Health Service officials assume that a "vaccine or therapeutic agent will not be available before 1990." Others at the hearing said that was optimistic.

Under the Reagan administration proposal delivered to Waxman last Friday, the budget for AIDS, acquired immune deficiency syndrome, would rise to $126.3 million and target:

*Monitoring and evaluation of donated blood and research into the HTLV-III virus that may trigger the disease.

*Studies to determine the nature and history of the HTLV-III virus and a demographic analysis.

*Education programs in every state to help explain the health risks and prevention techniques.

*Demonstration and evaluation projects and clinical tests of drugs that might prove effective.

The disease is fatal. According to data from the Centers for Disease Control (CDC) in Atlanta, 11,563 cases had been reported by July 1.

Health Service officials said yesterday that if trends continued, 40,000 new cases could be expected in the next two years, straining the American health-care system. AIDS patients' cost of treatment ranged from $50,000 to $140,000, according to a recent CDC study.

Dr. Paul Volberding of San Fransisco General Hospital said that even if only 5 to 10 percent of people infected with the HTLV-III virus contract the disease, their medical care could exceed $10 billion.

Like most other researchers at the hearing, Volberding called for more money for education: "In addition to an AIDS vaccine we need to support a much more vigorous program of public education. While AIDS is a complex disease, its transmission is well understood and preventable."