Although the Reagan administration has "withdrawn" its tough proposals to alter the way white collar federal pay is set, it may soon come forth with even harsher guidelines to scale down the size of future government raises.

In his budget the president said he was dropping the pending bill to revise the yardsticks used to compare wages of the government's million professional, technical and clerical aides with industry pay rates.

That bill came out of a Ford administration study. It was adopted by the Carter team. Reagan's people made it tougher by proposing to limit U.S. pay raises to 94 percent of the annual compensation increase for private sector, state and local government employes. It would also have linked federal and private pay on a geographic basis. U.S. workers in Detroit, San Antonio, Washington and other cities would have gotten hometown industry rates, rather than the same nationwide salaries as at present.

Congress ignored the pay plans. Thanks mainly to heat generated by former representative Gladys N. Spellman (D-Md.), rural and southern members balked at the geographic wage plan.

Unions opposed the pay proposal. They said it was a statistical gimmick designed to make federal pay rates appear better (in comparison with industry) than they are, and make it easier for the president to give smaller October increases.

Reagan's announcement that he was withdrawing his federal pay package caused some union leaders--who have their hands full with retirement cutback plans, budget reductions, RIFs and furloughs of members--to hope that they would not have a major pay fight this year. But congressional staffers, aides at the Office of Personnel Administration and union experts believe the administration will come back with an even tougher bill that would make the earlier pay-shaving proposals seems modest by comparison.

Although Congress ignored the Reagan pay plan last year, it endorsed the 4.8 percent U.S. raise he recommended. He said that is the amount that would have equaled "comparability" with industry IF Congress had approved his pay plan.

The General Accounting Office recently blasted the Reagan plan to set future federal pay hikes at 94 percent of the amount needed to bring federal salaries up to par with industry. Administration officials said the 94 percent figure was designed to reflect some federal fringe benefits--tenure, early retirement and the entire retirement package--that are difficult to measure but are considered more generous than industry's.

The administration may try to end-run the more pro-civil servant Governmental Affairs and Post Office-Civil Service Committees and take its case directly to the budget committees which are the new powerhouses on Capitol Hill.