The House Post Office-Civil Service Committee yesterday voted 15 to 3 to urge the House Budget Committee to include a 4 percent October raise for white-collar federal workers in its upcoming budget reconciliation bill.

If the Budget Committee okays the recommendation of the committee that oversees the federal work force, the October pay date will become part of the budget the House will propose as its spending plan for the government for the fiscal year that starts in October.

But if the Budget Committee rejects the October pay raise recommendation--as is likely--the matter will go to the House floor, where the date of the next federal pay raise will be voted on separately.

The first budget resolution approved by Senate-House conferees called for a 4 percent white-collar federal pay raise to go into effect next January. That represented a compromise between the October pay date originally approved by the House and the April 1984 pay raise date okayed by the Senate.

President Reagan opposes any increase in October, although data collected by the Bureau of Labor Statistics show that government pay is running behind the private sector by about 20 percent.

The Post Office Committee vote was along strict party lines. All Democrats voted for the October pay raise proposal. Three Republicans--Frank Wolf of Virginia, Connie Mack of Florida and William E. Dannemeyer of California--opposed it.

The fact that Wolf showed up to vote--four Republicans and six Democrats did not attend the meeting--and then voted no surprised a lot of people.

Wolf frequently has broken ranks with the Reagan administration on matters concerning federal workers, who make up a big chunk of his congressional district.

Wolf said he supports a much larger October raise for U.S. workers in October. But he said he objected to the committee action because it would mean a seven-month delay (until January 1985) in the next cost-of-living raise for retirees, would reduce that raise for retirees under age 62 and would give members of Congress a raise this October.