Federal workers who are due for 3 percent longevity step increases between now and next Monday will receive them under the present system, which emphasizes seniority over performance, rather than under a new White House plan, thanks to a weekend of confusing court activity.

All parties in the dispute over the proposed new performance pay and layoff rules are waiting for a sign from U.S. District Judge Thomas Penfield Jackson. He has until Monday to decide what to do with a union request to block the plan, being pushed by the Office of Management and Budget (OMB), that would make it tougher for some employes to get the step increases, and strip some job security from longtime workers.

Last Friday Jackson turned down a request by the American Federation of Government Employees' union for a delay in the new pay-layoff rules. But the next day the U.S. Court of Appeals blocked implementation of the regulations, directing the lower court to review the proposed delay.

Opponents of the new rules claim it would allow managers to arbitrarily punish workers by giving them poor annual performance ratings, thereby denying them step increases. Under the current system, 99 percent of all employes with enough time in grade get such raises. Nearly one-third of the government's million-plus white-collar workers get the increases each year.

The major opposition to the new rules, however, is in the area of layoffs. Government agencies now fire employes primarily under the last-hired, first-fired system. The new rules would make it possible for an employe of 20 years with average performance ratings to be fired before a relatively new worker with a series of "outstanding" job ratings.

Even if the judge allows the rules change to go into effect, Congress may override that decision. Senate-House conferees will meet next week to iron out a compromise federal spending bill for the remainder of this fiscal year, which ends Sept. 30. The House version of the bill contains a ban on the rules change. White House sources have indicated that while they favor the performance-based rules, the president would not veto the entire spending package if the House ban prevails in Congress.