If the Reagan administration persuades Congress to raise the standard government retirement age to 65, employes who are now eligible to retire under current age and service rules (nearly anyone over 55) will be able to retire as planned without taking any pension cutback.

The White House wants to require U.S. employes to work longer, and contribute more into their retirement fund, to get unreduced benefits.

Under present law employes can retire at 55 (with 30 years service) on an annuity equal to 56.25 percent of their high three-year average salary.Current law also permits retirement at age 60, with 20 years service. That produces an annuity equal to 36 percent of the salary average. Workers may also retire at 62 with five years of service and get an annuity equal to 7.5 percent of their average salary.

The administration proposal, if it survives in Congress, would impose a five percent annuity reduction on employes for each year under the age of 65 they retire.

The Office of Personnel Management says, however, that employes who are 55 or older at the time of enactment (regardless of how much time they have spent in government) could still retire under present rules. That is, they could retire at 55-30, or at 60-20 or 62-5 without any annuity cutback.

OPM says its plan would phase-in the penalty for retiring before age 65 over a 10-year period. Employes could still retire at age 55 with 30 years service even if the proposal became law. But their annuity would be subject to a reduction depending on their age at the time of enactment.

For example, an employe who was 55 years old at time of enactment could still retire after 30 years service without any penalty. A worker who was 54 could retire at age 55 (with 30 years service) and take an annuity deduction of "only" 5 percent.

An employe age 53 at time of enactment could still retire at 55 (with 30 years service) but would be subject to a 10 percent annuity reduction.

A worker who is 51 at the time of enactment would take a 20 percent reduction if he retired at 55 with 30 years service.

The reduction for someone age 49 would be 30 percent, and so on down the line.

Employes who do not reach their 45th birthday before the date of enactment of the proposal would take the full proposed 50 percent annuity reduction if they decided to retire at age 55 with 30 years service.

Younger employes, and those coming into the system in future, would be subject to the new 65 retirement rule.

Those who quit at 55 with 30 years service would take the full 50 percent reduction.

The administration plan is part of the budget. It has been formally outlined to Congress, but not yet introduced in the form of legislation.

Once it is introduced it is supposed to go through the House Post Office-Civil Service Committee. Most members of that committee oppose the higher retirement age. Chairman William Ford (D-Mich.) says he will try to bottle up the legislation.

But the administration could push its proposal through the budget reconciliation process, making it a part of the budget bill Congress must approve sometime this session. If that happens the Post Office-Civil Service Committee could be sidestepped.

Many observers think the Reagan retirement plan will have an easier time in the Senate. But that overlooks the fact that a very important member of the Senate, and of the Senate Governmental Affairs Committee is up for reelection in 1984. He is Ted Stevens of Alaska, the Assistant Majority Leader.

Stevens has usually sided with federal workers--he has a lot of them in Alaska--and if he opposes the higher retirement age it could be blocked in the Senate.

At this point the administration plan is nothing more than a proposal. It has not been introduced as legislation.

But the White House says it will be introduced shortly, and they will push hard for the changes.