Pentagon leaders, apparently stung by criticism that the Rapid Deployment Force promises too little too late for the Persian Gulf, have launched an effort to beef it up in a hurry.

The Army, Navy, Air Force and Marine Corps all have been asked to submit proposals for improving the Rapid Deployment Force, the umbrella name for a collection of existing military units earmarked to be rushed to distant trouble spots.

Although Deputy Defense Secretary W. Graham Claytor Jr. directed the reappraisal before the Iran-Iraq war broke out, the conflict has added impetus to the effort.

"That thing has really driven home that there are no good answers to the questions of how the hell would we get there and what would we do when we landed," one general said.

But high-ranking officers are apprehensive about this latest request from their civilian superiors for ideas about spending more on the RDF. They fear the money could come from existing projects, to keep the total Pentagon budget down, and not be made up later.

There is also a suspicion among many admirals and generals these days that such sudden interest in spending more money on defense is politically motivated and will not last.

Such suspicions aside, defense officials did confirm to The Washington Post that Claytor recently asked the Pentagon's Office of Program Analysis and Evaluation to get proposals from the services for strenthening the RDF.

The current RDF blueprint calls for spending billions on new transport planes, high-speed cargo ships and assault vessels to take troops and weaponry to the Persian Gulf and other hotspots before a worrisome situation could get out of hand.

Some military leaders complain that the RDF is just cosmetics, that quick-reaction forces have been in being all along, that a new layer of command relationships would just complicate matters. The RDF is commanded by Marine Lt. Gen. P.X. Kelly, who has deputies from the other services.

Congressional doubts have arisen over the last few months about both the RDF blueprint and its staging ports and airfields in Oman, Kenya and Somalia.

During the recent House debate on the Pentagon's $157 billion appropriation for fiscal 1981, for example, Rep. Jack Edwards of Alabama, ranking Republican on the House defense appropriations subcommittee, complained that the Carter administration has not faced up to how it would structure an RDF to handle crises in the Middle East.

"The president and the Defense Department are saying that we can continue to fulfill these commitments" in NATO and the Pacific " and take on a new commitment in the Middle East without much expansion of the force sturcture . . . . This is an impossibility," Edwards said.

Edwards contended that the United States must build more ships so it can cover the Indian Ocean theater and add men and women to the armed forces. "What lacks most of all," he continued, "is some policy guidance from the Defense Department as to how it plans to protect our vital interests in the Middle East and Indian Ocean."

Several senators have been expressing similiar comlaints, citing the Iran-Iraq war to underscore them. A question that has arisen in secret briefings of representatives and senators on the Iran-Iraq conflict, and is expected to be repeated in other briefings this week, is how the RDF would get to that region tomorrow, if it had to do so.

Congressional qualms about using ports and airfields in Oman, Kenya and Somalia center on whether the host nations would allow the United States to use them in a crisis. The governments, because of the peculiar political pressures in that part of the world, might have to deny access, it is argued.

Rep. Paul Findley of Illinois, ranking member of the House Foreign Affairs Middle East subcommittee, is one of the lawmakers pressing the administration to seek base rights from more stable countries. He said the British have islands in the Indian Ocean other than Diego Garcia which the RDF could use.

Another question on the horizon is how to pay for what the services do recommend for the RDF over the next few weeks. Raising the Pentagon budget would undercut Carter's effort to damp down inflation.