Almost three months after a new administration took office promising a definite and agressive foreign policy, several key officials charged with formulating that policy are still lingering in a bureaucratic twilight zone waiting for Senate confirmation of their appointments.

These include the assistant secretaries of state for each of the State Department's regional bureaus -- Europe, Africa, the Middle East, Asia and the Pacific and Latin America. In the case of the Latin American job, a position that includes responsibilities affecting such hot spots as El Salvador, the administration has not even sent the name of a proposed nominee to the Senate.

Other posts where administration nominees remain unconfirmed include the undersecretary of state for economic affairs, the assistant secretaries for economic and business affairs and for oceans and international environmental Development and the U.S. International Communication Agency.

Some of the delay in filling these posts in the normal result of various paperwork and security check requirements. Some of it results from the less and its committees at the start of a new Congress.

But much of it also has to do with the political dictates of the third-ranking Republican member of the Senate Foreign Relations Committee, Jesse A. Helms of North Carolina.

Helms, the guardian of conservative values for the Reagan administration and its foreign policy, has personally held up action on four of the five key regional bureau jobs in the State Department, according to John Carbaugh, Helms' legislative aide on the Foreign Relations Committee. These include the Latin American job, plus the nominations of Lawrence Eagleburger to be assistant secretary of state for European affairs, Chester Crocker to be assistant secretary of state for African affairs, and John H. Holdridge to be assistant secretary of state for East Asian and Pacific affairs.

Only the appointment of Nicholas A. Veliotes to be assistant secretary of state for Near East and South Asian Affairs has dragged along without help from Helms.

According to Carbaugh, the delays in gaining confirmation for these officials is of no particular concern to President Reagan's top aides in the White House. A deputy to White House chief of staff James A. Baker III said he was unaware of the situation in the regional bureaus at the State Department.The White House personnel office did not respond to inquiries about it.

But if the White House doesn't care, a liberal Democratic member of the Foreign Relations Committee, Sen. Alan Cranston (D-Calif.), does. Last week, as Crocker was about to leave on a two-week trip to Africa still facing a second day of confirmation hearings when he returned, Cranston fumed that he could not recall such lengthy delays in approving the top layer of State Department officials.

"The fault lies right here in the Senate," he said in reference to Helms.

In response, Helms has wrapped himself in the Constitution, asserting his sacred right and duty to advise and consent to the nominations, while the irony of a situation in which a liberal Democrat is pushing for confirmation of the Reagan nominees has not passed unnoticed by Carbaugh.

"If they want to rely on Alan Cranston as their prime backer in the Senate, that tells a lot about where they [the nominees] are coming from philosophically," Carbaugh said.

Helms is determined that the nominees be philosophically true to the conservative promises of the Reagan campaign, according to Carbaugh. Joined by other conservatives, he has, for example, help up the expected nomination of Thomas O. Enders, a career foreign service officer, to be assistant secretary of state for inter-American affairs, while pushing Lewis Tambs, a conservative professor of Latin American history at Arizona State University, for the job.

The logjam is expected to continue until at least the end of this month, when Crocker is scheduled to have a second hearing before the committee and Holdridge and Eagleburger are tentatively scheduled also to testify.

Only one other senator, John Glenn (D-Ohio), is holding up a State Department appointment. Glenn has raised conflict of interest questions about James L. Malone, nominated to be assistant secretary of state for oceans and international environmental affairs.