Premiums for health insurance, a must item that is fast becoming a personal budget-buster for U.S. workers, could be less painful in the future if Congress acts on proposals to change the system Uncle Sam uses to help employes pay their premiums.

When new insurance rates go into effect in January, it will mean that the average cost of a health policy for a typical civil servant will have jumped 55 percent in 12 months.

Higher health insurance costs, and the imposition of the new Medicare tax (1.3 percent of salary) next year will offset most of the recent 4 percent raise for most employes, and leave many lower-grade workers with less take-home pay in 1983 than they had this year.

To cut costs, thousands of retirees and workers may bail out of their present more expensive (and comprehensive) health plans later this year, in favor of plans that offer less coverage in return for smaller premiums.

But those who switch to less expensive health plans could still wind up paying $1,000 or more next year in premiums, and more than that out of pocket, if they are hit with medical problems not covered by some of the less expensive and less generous plans.

Two very different approaches to the health care cost problem are in the works:

The Office of Personnel Management is considering a voucher system. Under the plan, which OPM says is awaiting White House clearance, workers would be given a fixed amount each year to buy health insurance.

The voucher would cover most or all of their insurance premiums if they choose a basic-coverage plan, or a portion of the premium for so-called Cadillac coverage plans with better benefits. Under OPM's plan, retirees might be given slightly larger vouchers to buy their health insurance.

Rep. Mary Rose Oakar (D-Ohio), meantime, has introduced a bill that would maintain the present payment system, but would shift more of the premium cost from the employe to the government. Oakar chairs the House subcomittee overseeing the health program that is run on a day-to-day-basis by OPM.

Her bill would have the government pay 75 percent of an employe's health insurance premium. Currently it pays an average of 60 percent.

In addition Oakar would force all health plans to cover retirees; some now bar them. She would not let either OPM or individual plans raise or lower benefits unilaterally; she would require all plans to offer basic standard coverage for treatment of alcohol, drug or mental problems.

Backers of both approaches say they would improve the health program, and give employes a better shake. But reaching agreement on one or the other, or finding a compromise, may be difficult given the players and the issues involved.

Oftentimes on Capitol Hill, when legislators tangle with administration officials over policy matters there is a sense of no-hard-feelings, or an atmosphere of let's-have-lunch after the match.

But the ideological gulf between Oakar (and most Democrats on the Post Office-Civil Service Committee) and OPM Chairman Donald Devine is wide, often personal and bitter. One could assume that neither Oakar nor Devine has made the other's list of people they would like to be stranded with on a desert island.

If the administration pushes the voucher plan, the argument will be that it would make plans more competitive (offering the best benefits at lowest cost within the voucher price range) and force employes to be better shoppers.

Oakar distrusts the administration's motives. She thinks her proposal would make the government more competitive with the private sector where companies often pay a bigger chunk of employe premiums. She thinks forcing Uncle Sam to pay more of the premium would make him a better shopper and force insurors to hold down their costs.

Most feds probably don't care which method is used, provided they get good coverage at the lowest cost. But it may be hard for that to happen unless either Congress or the White House is prepared to give some ideological ground.