The sultanate of Oman, which is to play a key role in the American Rapid Deployment Force by providing access to Omani air and naval facilities, says it expects a great deal of U.S. help in return.

In an interview with The Washington Post, the minister of state for foreign affairs, Youssef Alawi, said Oman hopes to obtain between $200 million and $250 million worth of arms as grant aid from Washington in addition to $1 billion for the improvement of its military facilities. Alawi said that his country "would like to find out whether the United States is in a position to consider giving Oman some funds similar to what it is giving to other friendly countries in the Middle East."

It appeared he was referring to grant aid the United States now provides Egypt and Israel to cover a significant portion of their American arms purchases. The proposed grants to these two countries for fiscal 1983 are $400 million and $500 million respectively.

"We are expecting the United States to finance the buying of the arms," Alawi said. It was the first time a high-ranking Omani official has publicly stated what this strategically located nation, jutting into the Strait of Hormuz, expects to derive from the relationship developing with the United States.

"We are thinking about $200 million to $250 million for various kinds of equipment," Alawi said, indicating Oman was also beginning to consider acquisition of an advanced fighter capable of dealing with the American-made F14s in Iran's possession.

While studies of which plane would suit Oman's needs best were just beginning, Alawi said, an important factor in the final decision would be which country provided the necessary financing. He noted the American F16, the French Mirage-2000 and the British Tornado as the three possibilities.

Acquisition of sophisticated aircraft by Oman would also involve extensive training for Oman's armed forces, which rely heavily on British military personnel seconded to the sultanate.

Alawi said talks are under way with Oman's five other partners in the Gulf Cooperation Council about the joint purchase of Western arms "as part of a larger plan for Persian Gulf defense."

The wealthier members of the council--Saudi Arabia, Qatar, Kuwait and the United Arab Emirates--have agreed in principle to help finance the military needs of the poorest two, Oman and Bahrain, and a military delegation has already visited here in this regard.

Traditionally a British preserve and still heavily dependent on London, Oman appears to be testing the waters of its new relationship with the United States as well as studying the assets and liabilities of the U.S. connection on its increasingly important ties with the other gulf council members.

Initially, the sultanate was sharply criticized by some of the other Persian Gulf states, notably Kuwait, for signing an agreement in June 1980 granting access rights to Omani military facilities for the U.S. Rapid Deployment Force. That this is still a sensitive issue was made clear during the force's Bright Star exercises last December, when Oman refused to allow any Western press coverage of American Marines landing on the shores here.

The Gulf Cooperation Council, founded last May, is formally committed to keeping all superpower military forces out of the region and not providing "bases" to any outside nation. Although Oman has not technically given the United States any bases or allowed the permanent stationing of American troops here, its agreement with Washington has drawn criticism within the council and particularly from the Palestinian-influenced Persian Gulf press.

Alawi, who serves as Oman's foreign minister in everything but title, which Sultan Qaboos has kept for himself, gave no indication that his country has any intention of bowing to these pressures. But he did indicate mounting Omani concern about American policy in the Middle East and its possible adverse impact on the burgeoning relationship between the two nations.

The Omani official said U.S. improvement of various military facilities here was going ahead as planned after initial delay and confirmed press reports that Oman's "expectation" was that Washington would eventually spend between $1 billion and $1.5 billion on this.

"I think the figure will reach that amount," he said.

The United States has begun by allocating $280 million over a three-year period to upgrade four airports at Seeb outside Muscat, Khasab on the Hormuz Strait, Thamarit in the southern Dofar Province, and on Masirah Island. Most of this money is for the latter airport, which seems destined to become the main staging area in Oman for the Rapid Deployment Force because of its isolated location.

Alawi also spelled out other Omani "expectations" of U.S. assistance to his small nation in case of an attack from either the Soviet Union, Iran or Marxist South Yemen, the three main potential threats to its security.

He said there was "an understanding," although no formal, written agreement, that the United States would help defend Oman. Asked if this included sending American troops here, Alawi replied, "We do not expect U.S. combat forces. That is not in our minds unless the Soviets are involved."

In Washington, a State Department official had no comment on Alawi's suggestion of an unwritten "understanding" with the United States.

He said he thought the British-backed Omani forces could take care of themselves in any attack from Iran or South Yemen. Oman was only asking Washington to help by reinforcing "our capabilities by supplies and certain facilities."

"There are many ways we expect the United States to stand by us short of troops and aircraft," he remarked. "There are many other ways and means to find ourselves in a better position militarily."

He did not elaborate.

Alawi said Oman still regarded South Yemen, which backs an 11-year-long guerrilla conflict in the sultanate's southern Dofar Province, as the main danger to its security. He said the Yemenis still kept three brigades on the Omani border and were improving their air, land and naval positions there.

Speaking about the limits of American-Omani cooperation in the present political atmosphere in the region, Alawi said all Arabian Peninsula nations were "reluctant" to give the Rapid Deployment Force Command the right to base itself on their territory because of U.S. suport for Israel and the unresolved Palestinian issue.

"Politically, it is very difficult to do," he remarked, adding, however, that "I would not say impossible."

Asked whether Oman might be willing to host the command, Alawi said it was "too early to comment on this" but that no talks had yet been held.

"The United States needs to cooperate with the Arab countries to prevent Soviet expansionism," the minister said. "The primary way is to look to the Middle East problem and the Palestinian issue. That would ease the whole thing and change the whole picture for many Arab countries to cooperate with the United States rather freely."

Alawi warned that if Washington did not take steps to prevent what many Arabs perceive as the threatened Israeli occupation of south Lebanon or formal annexation of the West Bank, the new U.S.-Omani relationship might suffer a serious reverse.

"You cannot expect Oman to be taking a step that will isolate it from the rest of the Arab countries," he said.