Federal job forecasters are not cautiously predicting that there will not be a solid freeze on government hiring following the inauguration of President-elect Reagan.

Recommendations whether to freeze U.S. hiring or seek cuts in other ways are due from the Reagan transition team on or about Jan. 1. That is less than two weeks before he takes the oath of office.

Candidate Reagan said that one of his first acts as president would be to freeze government hiring until cabinet officers got a handle on their new departments and agencies. But the Reagan transition team -- which has turned out to be a very professional, quick study -- has learned a few things since it set up shop. One of them is that, aside from the political mileage of a U.S. hiring freeze, such a drastic step often causes more problems than it solves.

Old government hands who have been advising the Reagan team have, almost unanimously, suggested that he take other routes to reduce federal employment. Shortly after the election, a former top Defense aide of the Nixon and Ford administrations told Reagan officials to advise the president-elect to "stop making campaign promises." He specifically cited the job-freeze talk. Since then there has been little official mention of it, aside from breathless newspaper speculatin.

Full-time federal employment may be down 50,000 or more jobs by the time Reagan takes office. A partial freeze (one hire for every two departures) was imposed by President Carter in March. It has resulted in a reduction of nearly 21,000 jobs through September.

Officials anticipate that as many as 25,000 current U.S. workers may quit by Jan. 18, two days before the inauguration, to cash in on part of a 7.7 percent federal-military pension increase that went into effect last September. That so-called "look-back" benefit expires Jan. 18.

Senior bureaucrats advising Reagan transition teams in various agencies and departments are urging that cuts the president wants can be made better, and with less disruption to government, via selective freezes, budget and personnel ceilings. The next Carter budget will recommend fewer federal workers in most agencies and there is a feeling that if Reagan simply accepted them he could produce a slimmer federal establishment without resorting to a total hiring freeze.

The argument in favor of a total freeze is simple, and effective: Nobody gets hired, the government gets smaller by attrition rather rapidly. The antifreeze argument is more complex: It says that a total freeze reduces lower-grade, lower-paid jobs more rapidly since that is where turnover is greatest, and creates gaps in organizations that reduce their effectiveness. iAlso -- and statistics bear this out -- fewer people retire when a freeze is on. Older workers who would normally retire, especially in the Washington area, tend to hold onto their jobs, for a variety of reasons, when employment is frozen.

Reagan aides say that no freeze decision has been made. They acknowledge that other alternatives are being studied. That, in itself, is good news for job-seekers and workaday Washington, which doesn't handle any sort of freeze -- whether weather or employment -- very well.