Members of the armed forces will not receive a small tax break this year after all when the government shifts their official pay date, according to the Defense Department.

Maj. David Super, a Pentagon spokesman, said the upcoming shift in pay dates from the last day of the month to the first would normally mean that December salary checks would be distributed to employes Jan. 1.

"But since Jan. 1 is a federal holiday, a decision has been made to distribute those checks on Dec. 31," Super said. "There won't be any effect on the government since we're on a fiscal year."

The decision does mean, however, that members of the armed forces will receive all of their calendar 1987 pay in 1987, instead of receiving their December check in January. If the December check had been held until January, military personnel would have been able

to report a smaller income to

the Internal Revenue Service for

1987.

The shift in pay dates is scheduled to take effect this month, with the September checks being distributed Oct. 1. The shift, ordered by Congress last fall, changes more than a century of tradition of using the last day of the month as the military's official pay date.

By directing those in the armed services to wait an extra 24 hours to get paid this month, Congress was able to shift that payroll from the end of the government's fiscal 1987 to the start of fiscal 1988, which begins on Oct. 1.

That, in turn, allowed Congress to shift almost $3 billion in Pentagon salary expenses to the next fiscal year -- providing a relatively painless means of cutting the Pentagon's budget request without really cutting it.