Trial court officials have indefinitely suspended plans to demote probation officers who failed a controversial new exam as five officers filed discrimination complaints charging that the test was biased against minorities.

Twelve acting chief probation officers — half of them minority members — had been facing the prospect of a demotion and pay cut on Monday after they failed the essay portion of the exam. But court officials sent them a curt e-mail on Friday, saying that their demotions had been postponed “until further notice.”

“We will update you on this issue when there is additional information,” court officials wrote. “Thank you for your attention in this matter.”

The promotional exam was supposed to provide a more objective and fair hiring system for the Probation Departmentafter years of political patronage under former commissioner John J. O’Brien. But, after more than half of probation employees failed the essay portion of the test in March, some complained bitterly that the test had little to do with their jobs.

This week, the union that represents probation officers, NAGE, filed a grievance to permanently stop the demotions, which targeted probation employees who had been acting assistant chiefs for at least 18 months.