Scheduled increases in payroll taxes have ensured the financial health of the Social Security system for the next several decades, system trustees reported yesterday, and they warned Congress not to roll back those increases.

The warning, which came in the trustee's annual report, was issued on the eve of a scheduled meeting of the House Ways and Means Committee at which members may vote to reverse an ealier decision to roll back part of the increases scheduled for 1979 and 1980. The increases were approved by Congress last year, but Ways and Means voted 19 to 18 last Thursday to scale them down significantly.

The trustees said that as a result of increased scheduled to start taking effect in 1979 and subsequent years, the old-age and disability accounts would have sufficient funds to meet all needs until 2030, instead of facing disaster in the next few years. The Medicare accounts, hit by a "rapid growth" in hospital costs, will be healthy until 1990, but then will need new funds, they said.

They said that last year's action by Congress had put the old-age and disability funds on a sound basis, after years of uncertainty. "The recently appointed Advisory Council on Social Security is studying the long-range financial status f the Social Security program and will report their findings in 1979," the trustees deport said. "In view of these considerations, and the short time that has elapsed since inactment of the 1977 amendments, the board (of trustees) recommends that no action be taken to change the financing arrangements of the Social Security system at this time.

After the system will run into financial problems because of the aging of the U.S. population. When the huge baby boom of the 1940s and 1950s hits retirement age after the turn of the century, there will not be enough active workers left to pay for the retirees' benefits without further tax infusions.

At present, actuarial figures show, there are 19.1 persons 65 and over for each 100 workers ages 20 to 64. By 2030 there will be 33.8 persons 65 and over for each 100 workers ages 20 to 64.

The secretaries of the Treasury, Labor, and Health Education and Welfare departments are the trustees of Social Security.