Some federal agencies will resume hiring later this month on a limited basis. If you are one of the people denied employment because of President Reagan's post-election job freeze this is a good time to check with the agency that promised you a job before the great Jan. 20 back-off.

The Office of Management and Budget is mailing "allotment letters" to more than 100 federal departments and agencies. The letters give new dollar and job ceilings based on general, government-wide proposals from the Reagan Budget.

Once federal agencies have the allotment letters it will be up to them to decide whether to stick with the hiring freeze. Those slated to lose lots of jobs will probably keep the freeze on most hiring. The idea is to trim the work force via attrition and minimize the need for major RIFs reductions in force) of workers. Departments at or near the new Reagan job ceilings (some are actually below it thanks to the freeze) can start hiring. Defense for example, is to get more jobs in Reagan's budget. It lifted the hiring freeze last month and is bringing in new people again.

OMB's allotment letters will, in most cases, give federal agencies the authority to process "hardship cases" of individuals promised jobs between Nov. 5 and Jan. 20. Reagan canceled job promises made during that period. His authority to do so has been upheld by a federal court. Nobody knows how many people were promised jobs during that period. A guess-timate is that 20,000 people were denied employment because of the freeze. Some will get jobs once agencies have permission to handle their own hardship cases.