Donald J. Devine, director of the Office of Personnel Management and the self styled "Grinch" of the civil system, yesterday gave a sneak preview of a merit pay raise system scheduled to go government-wide by midsummer.

Devine told an OPM audience -- mostly supervisors and managers who got the raises -- that top increases would average 9.2 percent, compared to the 3 1/2 percent raise that went into effect this month for rank-and-file civil service workers who are now outside of merit pay.

He said OPM is the first agency to make the performance-based payouts under merit pay rules that Congress modified last summer. That merit pay system now covers about 108,000 supervisors and managers in Grades 13 through 15. About 50,000 of the employes are in the Washington area.

Devine said he hopes a similar performance-based pay system, tying raises to annual job appraisals, can be implemented later this year for most other white-collar workers. Congress last year voted to make it possible for merit-pay workers to get bigger salary increases and bonuses, but blocked extension of the system to other workers until July 1985.

All but five of OPM's 519 merit-pay supervisors got merit raises based on performance ratings of "outstanding," "exceeds fully successful" or "fully successful." Workers covered by the merit pay system are in the $37,000 to $67,000 pay range and can get merit increases ranging from 1 to 10 percent, plus one-shot cash bonuses. Some OPM employes got bonuses of as much as $6,000, Devine said, and 22 got $3,000 or more in cash awards.

The OPM chief, who has helped engineer a major restructuring of government programs, budgets and nondefense job cutbacks, said he was delighted to be the bearer of glad tidings for a change. He said the administration intends to implement a similar performance-based pay system for other federal employes starting in July, when the congressional ban expires.

Under a civil service "reform" set up during the Carter adminstration, the government's 1.2 million white-collar workers were split into two different pay and reward systems.

Employes in Grades 1 through 12 get regular annual pay raises (the increase this January was 3 1/2 percent) plus longevity raises (each worth about 3 percent) every one, two or three years, depending on how much time they have in grade. About 99 of every 100 workers who meet the longevity requirements for the within-grade raises get them, according to OPM. Under a performance-based incentive system, OPM estimates that 97 percent of all employes would still get the step-pay increases on time.

Workers in Grades 13 through 15 who are under the merit pay system, however, do not automatically get full annual pay raises or within-grade increases. Raises for them are based on their annual performance ratings.

Congress revamped the merit pay system last year because of complaints from supervisors and managers that the increases they got, even for outstanding performance, often didn't make up for the loss of step increases.

OPM's payout policy -- if it is adopted by other agencies -- would guarantee more generous raises for merit pay workers.

Federal employe unions have opposed extending the merit pay system down into the civil service ranks. They argue that it would make it easier for bosses to withhold raises from employes for political or personal reasons unrelated to their performance.

Devine was unusually upbeat yesterday, and he said the OPM payouts prove that merit pay works and provides an incentive for managers to cut costs and boost productivity.