The Reagan administration appears to have written off India in formulating its policies for South Asia and the Persian Gulf, deciding there is no way Washington can pull closer to the government of Prime Minister Indira Gandhi without compromising its wider global interests.

As a result, all that U.N. Ambassador Jeane J. Kirkpatrick offered India during her visit here this week was the promise of more consultations that possibly could lead to the repair of longstanding, misunderstandings between the world's two largest democracies.

American diplomats in Washington have said they will listen to all of India's arguments, but indicated they will pay them little heed. Diplomats in the Indian Embassy have noted that they get a ready ear in the State Department these days, but their views do not appear to carry any weight with U.S. policy makers.

"It seems to me," a senior U.S. official said here this week, "that no nation as large, as populous, as actually and potentially powerful as India could be judged permanently irrelevant to the foreign policy of the United States."

The operative word, according to close diplomatic observers of Indo-U.S. relations, is "permanently."

For the time being, however, the Reagan administration has rejected India's apprehensions about the U.S. policy of selling arms to Pakistan and keeping a strong naval presence in the Indian Ocean, although Kirkpatrick promised to bring New Delhi's concerns to President Reagan and Secretary of State Alexander M. Haig Jr.

To bow to India's wishes on those two issues would require a major about-face on a cornerstone of Reagan administration foreign policy -- the protection of vital oil routes through the Persian Gulf and the Indian Ocean, which Kirkpatrick said are threatened by 85,000 Soviet troops in Afghanistan, Soviet bases around the Horn of Africa and the Soviet fleet in the Indian Ocean.

Gandhi, however, sees the buildup of U.S. forces in the Indian Ocean and the American rearming of Pakistan, especially the sale of top-of-the line F16 fighers, as the greatest threat to peace in the region. She has explained the Soviet move into Afghanistan as a result of Washington's threatening behavior in the region.

Explaining Reagan administration policies, Kirkpatrick said Soviet efforts to "establish hegemony" in the Persian Gulf and Indian Ocean threaten "the stability of the region and the national independence of nations in the area.

"That is too great a threat to be endured passively by nations who are dependent upon the energy sources of the Gulf region or the sea lanes through the Indian Ocean," she declared.

Improved Indo-U.S. relations are further complicated by the determination that India's close economic ties and strong defense relationship with the Soviet Union "often lead to a pattern of voting and speaking at the U.N. and other international forums which are different and in frequent conflict with our perspectives and our voting patterns," said a senior U.S. official.

That official appeared to be referring to India's becoming the first noncommunist nation to recognize the Soviet-backed, Vietnamese-installed government in Cambodia; New Delhi's absentions in two U.N. votes condemning Moscow's invasion of Afghanistan, its original speech in the General Assembly lending support to the Soviet move and its draft resolution at the conference of the nonaligned movement that hedged on condemning the Soviet occupation of Afghanistan.

On the other hand, some diplomats here see signs that the Gandhi government is trying to put distance between itself and the Soviet Union.

They cite especially Gandhi's refusal to make a big deal out of the 10th anniversary of the Indo-Soviet friendship pact, which was celebrated with great fanfare in Moscow this month.

Nonetheless, said a senior U.S. official, "India thinks of our foreign policy as reflexively anti-Soviet and I'm afraid we think of India's as reflexively pro-Soviet.

"That does not lead us to the conclusion that India is part of any Soviet Bloc or that India is irrevocably wedded to the Soviet Union," the official continued. "On the contrary, we would not be talking of closer consultation or improved relations with India if we believed it is part of the Soviet Bloc."

The official noted, however, what the Reagan administration believes are "exclusively anti-American trends" in Indian foreign policy in recent years that go beyond what is seen as its pro-Soviet tilt.

For instance, India refused to support any U.S. or U.N. sanctions against Iran for the holding of the American hostages and instead sent a trade delegation to Tehran to try to capture some of the business previously done by U.S. companies.

There appears to be no inclination on the part of the Reagan administration to send a final shipment of enriched uranium for the nuclear reactor at Tarapur, approved by Congress last year, as a gesture of good will to India.

On the other hand, there is little indication here that the Gandhi government would reciprocate with any similar gesture, said a longtime American student of India with no government connections.

One Western diplomat with long experience in this country suggested there is little any U.S. administration can do do improve relations with India short of giving it a veto over all U.S. policies in the region and allowing it to deal as it wants with its neighbors.

No U.S. government is likely to allow India to dictate its regional policies, the Western diplomat said, though Reagan administration statements on South Asia generally include the truism that India is the predominant power in the region.

Indians sometimes appear to wonder if Washington really means that, and, if it does, ask why the United States continues to move closer to Pakistan.

Kirkpatrick, addressing that Indian question, accused the Gandhi government of trying to force the United States into taking an "either-or" approach in its dealings with India and Pakistan instead of letting it be friends with both nations.

Kirkpatrick tried to assure India that arms the United States sells to Pakistan are no threat to India, despite three wars in the 34 years since the two countries became independent.

"We have declined to accept the notion," she said, "that we cannot have normal friendly relations with both India and Pakistan. . . .

"Now it may be that Indians are saying 'No, you can't do that.' But I would say that I find this a rather surprising perspective to be so widespread in a nation which is the intellectual father as well as a founder of the movement of the nonaligned."

It appears to some diplomats here that India is more concerned about a break in economic relations with the United States than the political differences dividing the two nations.

Although India is proud of its self-sufficiency and economic progress, it remains heavily dependent on soft loans from multilateral lending institutions, such as the World Bank, which receive the largest portion of their funds from the United States.

India is the World Bank's biggest borrower, taking about 40 percent of its funds. There are indications that the Reagan administration wants to cut the U.S. contribution to those international institutions, which could throttle India's economic development program.

Despite the wide political differences between the United States and India, it appears that the Gandhi government would like to retain some measure of influence in Washington to play a role in shaping U.S. policies toward international lending institutions.

It is this fear of losing soft loans, said one knowledgeable Western diplomat, that does most to moderate Indian attacks on U.S. policies in the region.

Nonetheless, the chasm between the United States and India appears larger now than at any time in the past, and U.S. charge d'affaires Archer K. Blood has said publicly that relations are unlikely to improve in the near future.