On Wednesday, Mr. Clinton plans to offer a major initiative to help working families obtain child care, with a variety of new Federal subsidies and tax breaks. Administration officials and Congressional aides said the package would cost $20 billion over five years.

Congressional aides said they had been told that the package would include more than $7 billion to bolster the Child Care and Development Block Grant, which provides money to states, mainly to subsidize child care for low-income families. The President will also seek an increase in the Federal income tax credit that parents can take for child care expenses, at an estimated cost of $5 billion over five years.

The President's plan will also include a new tax credit for businesses that establish or run child care centers for workers, or reserve places in existing centers. Mr. Clinton will also ask Congress for money to improve the training of child care workers, to finance care for older children after school and to expand the Head Start program for preschool children. The proposals are all subject to approval by Congress.

Administration officials said today that the Medicare proposal was designed to aid those who had lost jobs and health benefits in the corporate downsizing of the past decade. Private insurance for the healthiest people ages 55 through 64 costs $5,000 a year or more, while those with chronic illnesses like diabetes, high blood pressure, ulcers and kidney ailments often find they cannot buy private insurance at any price.

There are 22 million Americans ages 55 through 64; roughly 3 million of them now have no health insurance. Administration officials estimate that 300,000 people in this age group will take advantage of the Medicare proposal, if it is enacted.

But the plan is designed to deal with the baby boom bulge of people in that age group coming after the turn of the century. By 2010, there are expected to be 35 million such Americans, and if the current reductions in employee benefits continue, there will be many millions more without health care coverage.

The Administration plan would allow those ages 62 through 64, who want Medicare coverage, to buy into the program for about $300 a month. When they become eligible for full Medicare benefits at 65, they would then have to pay $10 to $20 a month above the premium for physician services, which is now $43.80 a month. Hospitalization for Medicare recipients is paid for by payroll taxes on current workers.