Many of the top press, personnel and administrative jobs in government -- the key operations in an agency -- will be opened to noncareer (political) appointees in coming months.

Traditionally those jobs, which shape the image of the agency and the person running it, determine who gets in and moves up and controls day-to-day housekeeping functions, have been held by career civil servants. They often have frustrated their political masters who know they have only a short time (compared to the career people) to make changes, or shift directions of government departments.

Under the new SES (Senior Executive Service) many of those key positions, which were career-only, either by tradition or design, will be opened up to noncareer appointees from inside and outside government. They will serve at the pleasure of the agency head without the tenure rights, or the long-term investment to the bureaucracy that career employes have.

Agencies currently are designating which jobs will be reserved for career employes only, and which supergrade slots -- Grades 16 through 18 -- will be reserved for career people, or opened up to noncareer (political) appointees as well.

The SES is the cornerstone of President Carter's new program to reform the civil service, and make the federal bureaucracy more "responsive" to appointees of the president.

(Officials agree that the term "responsive" has a Nixonian ring. But they say the Nixon people tried to make the bureaucracy responsive for political reasons, while the Carter team wants only the leanest, best government possible.)

Although the civil service reform act was billed as an overdue way to make government more effective, by giving managers power to reward and punish, it is expected to have little impact on the mass of civil servants at Grades 12 and below.

Most of the new rewards and punishments are limited to mid-level managers and supervisors, and to SES personnel. In fact, most of the protective job insulation that will be stripped away from bureaucrats will be taken from supergrade-level workers who will make up the SES, which goes into operation later this year.Most are located here.

Incumbent federal supergraders will not be forced to join the SES. But failure to enlist for the new higher-risk, higher-reward system almost certainly will lock an employe into place for the rest of his or her career. Promotions and better assignments generally will go to SES members.

Agencies now are deciding which jobs will be left "career only" and which will be opened up for either career people or noncareer appointees. A spot check by this column shows it is a "mixed bag" so far, but that many more public affairs jobs, top personnel slots and other key positions will be made available to noncareer personnel when the SES gets rolling. By law only 10 percent of the SES can be noncareer or political, but agency heads have great latitude as to which jobs they can set aside for political appointees.

Jobs such as auditors, inspectors and related fields will be reserved for career workers only. Insiders say that, judging from agency plans so far, most public affairs jobs in agencies will be designated "general," meaning they can be filled either by a career or noncareer employe. The same is true for top personnel jobs, which now are overwhelmingly held by career employes. The chief administrative jobs designated by agencies so far are split between "career reserve" and general, meaning either career or political.

If a large number of those key jobs are opened up to noncareer employes, it certainly would make agencies more responsive to the White House. The question is whether the public is better served by a bureaucracy that is responsive, or aloof from political leaders. Look for the answer here, in about five years.