Premiums most federal workers pay for health insurance coverage for themselves and their families will go up next year under new rates approved by the government to be announced today.

In the case of employees who are covered by Blue Cross-Blue Shield - and that is seven of every 10 workers -the biweekly premium for high option family coverage will jump $3.34 beginning in January. For workers who have, or elect the second largest carrier in the giant federal health program, Aetna, the high option family rate will increase by $1,77 for each two-week pay period.

Last year Blue Cross-Blue Shield and Aetna actually decreased the pre-rates for the high option family plan went up only $1.15 per pay period mium to employees by $3.74.

With only a few exceptions, most of the 60-plus plans in the government-backed health insurance program - covering 3.2 million active workers and retirees - will be allowed to raise 1978 rates anywhere from 10 per cent to 15 per cent.

The jump in health premiums, which federal officials say is still below increases that hive hit private sector workers, reflects the rapidly rising cost of health care - particularly for hospitalization.

Rep. Gladys N. Spellman (D-Md.) whose House subcommittee oversees the federal health program, blasted the rate incresases. She said they make it clear that Congress, the White House and the health care industry must work to slow the growth of health insurance costs.

For some lower paid federal employees, the 10 per cent to 15 per cent premium increase (which is split between workers and their agencies) will cut into the 7.05 per cent pay raise workers got earlier this month. Most employees won't actually get the pay increases until early November, and the new higher premiums will go into efect in January.

Blue Cross - Blue Shield and Aetna are two of the "big six" carriers on whose rates the government bases its average contribution level. In the case of the Blues' plan, the 1978 premium for high option family coverage will cost the government $26.49 per pay period and the employee will pay $24.86. For the high option, self only plan the government will pay $10.98 and the employee $11.17 every two weeks.

Aetna subscribers will pay $7.49 for self-only high option coverage and the government will pay $10.98 of its costs. The breakdown for family high option coverage is $26.69 for the government and $13.72 the employee.

The two union plans in the "big six" category will also go up. The National Association of Letter Carriers plan will raise its high option family rate premium $1.69 per pay period. SUbscribers will pay $17.05 and the Postal Service $26.69.

The American Postal Workers Union plan in 1978 will have one of the smallest premium increases, going up only 14 cents for self-only high option coverage and $1.42 biweekly for high option family coverage.The other members of the Big 6 carriers are two Kaiser Foundation Health plans based in California.

Blue Cross-Blue Shield will not offer any improvements - or cutbacks - in 1978 benefits. Aetna will change benefits to cover speech therapy in certain cases, and provide benefits for mental disorders, alcoholism and drug abuse in nonhospital centers not previously covered.

Group Health Association here will raise high option premiums $2.32 biweekly to the government subscriber and by 70 cents for self-only high option coverage.

Several of the plans will drop low-option coverage (offering lesser coverage at lower premium rates) althogether next year. They include the American Federation of Government Employees Health Plan; the Alliance Health Benefit Plan and the Government Employees Hospital Association. Persons enrolled in those plans who remain in them in 1978 will automatically be switched to high option coverage, and rates.

Federal workers should study the brochures available from their offices to determine which plan, premium and type of coverage is best for them. Employees will have an "open season" period - between November 14 to December 9 - in which to make changes in their health insurance coverage, or the plan they wish to belong to in 1978.