The chairman of a House health subcommittee charged yesterday that newly published Medicaid regulations "deliberately" violate the will of Congress and authorize far deeper slashes in services to children than was intended in the budget bill.

"This will have a devastating effect on the health of hundreds of thousands of poor children," said the chairman, Rep. Henry Waxman (D-Calif.).

A spokesman for the Health and Human Services Department said HHS believed the regulations were consistent with legislative intent. But the Children's Defense Fund, joining Waxman in objecting to the new rules, disagreed and said it is considering a lawsuit in an effort to block the regulations.

"The conferees on the budget bill intended every step of the way to protect children under 18," said Sarah Rosenbaum, a CDF attorney. "The regulations go the other way. There are nearly 750,000 medically needy children now in 33 states who depend on Medicaid cards for essential medical services."

The regulations that angered Waxman and the CDF do not involve the basic Medicaid program for people who are on welfare, but involve optional programs in more than 30 states for people just above the welfare line who are called the "medically needy."

Waxman said that the budget conference committee made clear that any state choosing to have a "medically needy" program must provide outpatient services to all children in this group who are under 18. The administration's new regulations, Waxman said, would permit states to limit coverage to some groups of medically needy children under 18 --such as those in foster homes or nursing facilities. He said the regulations also violate congressional intent in allowing states to lower income cut-off levels excessively in defining the "medically needy."

In a series of briefings over the past week, Office of Management and Budget Director David A. Stockman has revealed plans to seek deeper cuts in Medicaid and Medicare, or new requirements that recipients pay more from their own pockets.

Stockman said the proposals might include the introduction of co-payments and deductibles in Medicaid basic services, and he floated the idea of charging Medicaid patients a dollar a day for their hospital stays.

Stockman said the administration also might propose further tightening of eligibility requirements for other entitlement programs--including school lunches, guaranteed student loans and food stamps--by lowering the income level at which people might be admitted to the program or by permitting fewer exclusions from income. He said attention might also be given to federal employe retirement benefits, which he said had "gotten totally out of kilter due to overindexing." All told, he said, cuts in entitlement programs would probably total $2.6 billion in fiscal 1982 and rise to $15 billion in 1984.

While Waxman was assailing the Medicaid regulations, Blue Cross and the Health Insurance Association of America, representing all the private health insurance giants, were assailing the "medical competition" bills on which the Reagan administration hopes to base a still-unseen plan to bring medical costs down.

The competition bills propose such changes as giving retirees government vouchers enabling them to buy their own Medicare coverage from private insurers, or taxing workers on employer contributions for health insurance coverage to reduce the demand for expensive group health policies.

At a Ways and Means Medicare subcommittee hearing, the organizations said none of the bills introduced so far appeared capable of bringing down costs. In fact, they said, it is conceivable that these proposals could raise costs, increase government regulation and distort the health services system.