Social Security is in strong financial shape and will be able to pay all old-age and disability benefits well into the next century, the system's trustees reported yesterday, but the Medicare hospital insurance program faces bankruptcy by 1996, two years earlier than projected last year.

In their annual report on the condition of the giant system, which will pay out $202 billion in old-age and disability benefits and $76 billion in Medicare benefits this year, the trustees called for new steps to strengthen financing of the hospital fund.

Rep. James R. Jones (D-Okla.), chairman of the House subcommittee on Social Security, said the figures on the old-age and disability funds are evidence that American workers can depend on getting benefits when they retire. But he said these two funds should be administered by an independent agency so that there is no temptation for government officials to use them for other purposes, as he said had happened recently when funds were borrowed by the Treasury to make up a shortfall in general government operating funds.

The trustees -- the secretaries of the treasury, labor, and health and human services, plus two outside public trustees -- issue a financial report each year. It shows the status of the system over the next 75 years under four different economic and demographic scenarios: optimistic, moderately optimistic, intermediate and pessimistic. Officials usually consider the intermediate scenario the one most likely to come to pass. This year's projections were not much different from last year's.

According to this year's report, the old-age and disability funds are expected to build enough reserves over the next generation to pay all benefits through the middle of the next century under all scenarios except the pessimistic. Even then, benefits are safe until 2025.

Although the intermediate scenario yields a long-range deficit of .44 percent of taxable payroll, that shortfall is so small that experts consider it negligible.

The bleak 1996 projection for Medicare does not include the impact of provisions of the Reconcilation Act passed by Congress, which are expected to cut Medicare costs and perhaps make the fund last until 1997.