Federal retirees would get more money to help with health insurance premiums than active duty workers if the government moves to a system of giving its personnel fixed dollar amounts to apply to insurance premiums.

The Office of Personnel Management, as reported here Tuesday, is considering a proposal that would scrap the complicated method the government uses to arrive at percentage formula payments for insurance and instead give all workers and retirees the same dollar amount.

At present the government's share of health premiums is based on 60 percent of the average high option premium charged by six of the largest carriers in the federal health program, which has 126 plans. Because of the averaging system, the actual dollar contribution (the maximum is slightly over $39 per pay period) varies depending on which plan the worker or retiree chooses. In some cases it covers less than half the premium cost while in others it pays up to 75 percent of the premium.

The proposal being discussed at the OPM would give every active-duty worker the same dollar amount to be applied to purchase of insurance. It would be enough to cover the entire premium for employes who chose inexpensive, low-option, minimum-benefit plans. Workers who wanted more protection could buy it, paying the difference out of their own pockets.

Because retiree health needs are often greater, and because retirees have less money than active-duty workers, OPM is considering a two-tier system that would give retired government workers larger payments than active-duty workers.

The dollar payment plan is still under discussion. If the president approves it, Congress would have to approve the change. Insiders say it will be part of a major package of health care cost reforms that the Reagan administration will propose in February.

The idea is to create more competition in the nation's health insurance field by giving fixed payments to individuals who would then shop around for the best insurance deal for themselves.

OPM would certify carriers for participation in the federal health program but would no longer dictate rates or benefits the carriers offer. OPM officials say they would, however, insist that any carrier participating in the federal health program offer group rates, to keep premiums as low as possible.