The Office of Personnel Management yesterday gave health plans that cover about 55 percent of the federal work force until Monday to decide if they want to offer their subscribers refunds on their premiums.

OPM and the White House have approved Blue Cross-Blue Shield's unprecedented proposal to give back $289 million in premiums to current subscribers, and to refund $465 million to the federal health program. The refunds -- to be paid to 1.5 million Blue Cross-Blue Shield policyholders -- are possible because people haven't used their insurance plans as much as anticipated and because subscribers are paying a bigger share of their medical and hospital costs.

Many of the 300 other plans in the federal health program have had the same decline in utilization as Blue Cross-Blue Shield. But none has yet proposed a refund.

Most of the health plans would prefer to plow any potential refund money back into the health program to help hold down premiums or improve coverage or both. Worldwide, about 10 million people, including about half the population of Washington, are covered by the federal-postal health program. Blue Cross- Blue Shield is the largest health plan in the program.

Although most of the health plans consider the rebates the least desirable way to cut down their financial reserves and improve the health program, publicity surrounding the Blue Cross-Blue Shield rebate has put pressure on them to offer similar refunds.

OPM yesterday sent notices to all the health plans advising that the Blue Cross-Blue Shield refund has been approved, and telling them to make any refund proposal they may have by Monday. OPM and the White House have the final word on whether to approve refunds.

Refunds to federal workers who are currently enrolled in Blue Cross-Blue Shield will range from $18 to $374 and be tax-free. They will be sent as soon as possible, according to the company.

The Reagan administration supports the concept of refunds to both employes and retirees, and OPM is drafting legislation that would make the retiree refunds possible. Because the federal law that covers health plan refunds mentions only "employes," the Justice Department says special legislation must be approved by Congress before those refunds can be made.