The Reagan administration appears ready to nominate Daniel H. Kruger, a Michigan State University professor and veteran labor relations expert, as director of the Federal Mediation and Conciliation Service.

Administration sources said yesterday that Kruger is the most likely to get the post, which has been filled by Kenneth E. Moffett, both as acting director and interim appointee, for more than a year.

"I believe Kruger's nomination is imminent," a key administration official said yesterday. Kruger, 60, has been interviewed by Labor Secretary Raymond J. Donovan and other administration officials.

Another administration official said Kruger "is the White House favorite." But the official warned that "not everyone has signed off" on the proposal to nominate Kruger for the job.

Kruger, reached by The Washington Post, said he has not been contacted by the White House about any nomination. "I know I'm a candidate, but this thing has been in abeyance for some time," he said. He also said he wants the job.

Moffett, a Democrat, has won praise from management, organized labor and the media for his work last year in the baseball strike and the air traffic controllers dispute. But Donovan conceded last month that the hunt is for a Republican.