A House Ways and Means subcommittee voted yesterday to curtail Medicare spending $5 billion to $6 billion over the next three years, but balked at forcing federal employes to pay the Medicare part of the Social Security tax.

The spending cuts, drawn from a list put forward by Rep. Willis D. Gradison Jr. (R-Ohio) would be the largest ever imposed in Medicare, the health program for the elderly and disabled, but would fall far short of the $11.5 billion over three years required under the congressional budget resolution adopted last month.

By contrast, the Republican-controlled Senate Finance Committee three weeks ago approved $13.3 billion in Medicare cuts over three years. In addition, it voted to raise $2.4 billion in new revenues from fiscal 1983 to fiscal 1985 by making federal employes pay the Medicare tax, which this year is 1.3 percent of the first $32,400 in pay.

The House subcommittee sent its proposals to the full Ways and Means Committee, which may act on them later this week. The proposals will not necessarily reduce Medicare spending, which grows each year with inflation and population, but will keep it lower than it would otherwise be. They consisted mainly of fairly straightforward cuts in Medicare payments to hospitals and doctors, plus a plan to shift some Medicare costs to private insurers by making employers continue group health coverage for people who keep working past 65.

But the subcommittee also sent forward without recommendation a new proposal: a possible start on a Medicare "voucher" program, under which beneficiaries could, if they chose, get payments to buy health insurance from private companies instead of accepting Medicare benefits.

Congressional Democrats have been sharply critical of the domestic spending cuts insisted upon by President Reagan and called for in the budget resolution, particularly those in Medicare, and have made clear they will not take the lead and the heat in making any cuts.

At yesterday's meeting, they offered no plan of their own, deferring to Gradison. His proposals added up to the $11.5 billion over three years in cuts required under the Republican-engineered budget resolution, but as he emphasized, they did not include any Medicare changes that directly increased premiums or out-of-pocket costs to patients, as the Senate Finance bill would.

In a series of votes the Democratic-dominated subcommittee knocked Gradison's proposed $11.5 billion back to about $5.9 billion and possibly less; one proposal's impact was not clear.

As to government employes, Gradison noted that the vast majority qualify for Medicare after paying only small amounts into the trust fund during a few years of employment in the private sector. Rep. Charles B. Rangel (D-N.Y.), subcommittee Chairman Andy Jacobs Jr. (D-Ind.) and Harold E. Ford (D-Tenn.) voted nevertheless against taxing federal employes, while Gradison, John J. Duncan (R-Tenn.) and Beryl Anthony Jr. (D-Ark.) voted for it; it failed on the tie.

Also rejected, by voice votes, were a new restriction on how much doctors can raise their Medicare fees each year and a proposal to discontinue a 5 percent bonus now paid hospitals for nursing costs associated with Medicare patients. Gradison did not force a vote on additional proposals to limit payments for such "ancillary" hospital services as blood tests or X-rays or pay hospitals fixed costs in advance for certain services rather than costs actually incurred.

Jacobs, referring to one change which saved money in 1983 simply by deferring a payment until the fiscal year ended, likened it to a situation in which, he said, "Mutt told Jeff, 'I'll turn on the flashlight and you climb the beam,' but Jeff replied, 'You must think I'm stupid. When I get halfway up you'll turn off the light.' "