Postal workers who bargain with management and blue-collar federal employes get bigger raises than the nation's 1.4 million white-collar civil servants who depend completely on Congress and the White House to set their salaries.

A new study by the General Accounting Office says that over the last nine years the percentage pay raise for 600,000 postal workers has been nearly double that of government scientists, secretaries and other white-collar employes.

During the period, when living costs rose 113 percent, postal pay increased 123 percent and federal blue-collar pay rose 111 percent, while white-collar (GS) salaries went up less than 70 percent, GAO says.

White-collar federal workers are spread through 18 pay grades, ranging from $8,342 to $58,500.

Their national average salary is between $22,000 and $23,000.

Metro Washington's 330,000 white-collar workers average about $26,000.

The majority of the postal service's highly unionized work force is concentrated in the clerk-letter carrier grade levels starting at $21,400.

The average salary for nonsupervisory postal workers is $21,329.

Postal workers -- through their unions -- bargain directly for wages, fringe benefits and on other working conditions.

The government's half-million blue-collar (wage board) employes, who include laborers, mechanics and skilled craft workers, have their salaries set according to the prevailing wage in similar hometown industries.

Blue-collar workers would have received more than they did, except Congress put a lid on wages in some of those years.

GAO made the pay study for Rep. Mary Rose Oakar (D-Ohio).

Oakar, who heads the House compensation and employe benefits subcommittee (of the Post Office-Civil Service Committee) said the data shows the federal pay system "is in a shambles because the administration has abandoned any attempt to link federal pay increases to comparable work in the private sector as required by law."

White-collar federal employes are supposed to get pay increases designed to keep them on a par with private industry scales for similar jobs.

But in five of the last seven years, presidents -- Republican and Democrat -- have shaved the so-called "comparability" increase.

Oakar says the GAO report makes it clear that the "best and brightest career employes will flee the federal sector for better-paying, comparable work in the private sector at the first opportunity."

The budget being worked up by Congress proposes a 4 percent pay raise this year for white-collar federal employes, even though data from federal pay experts indicate workers are due increases more than three times that amount.

Both Presidents Carter and Reagan have proposed that Congress change the way white-collar federal pay is measured against industry, by including the value of fringe benefits and measuring for the first time salaries paid nearly 13 million state and local government workers.

Federal unions oppose the so-called "total compensation" system. They feel the government would use it to produce artificially low future pay-raise recommendations for white-collar employes.