NEW YORK. - Some three months, six million refugees and many thousand deaths after Pakistan's President Yahya Khan ordered the army to "normalize" the situation in East Bengal within 48 hours, the great powers and the United Nations are as unwilling to involve themselves with the politics of Pakistan's tragedy as they have been from the beginning.

This is not to say that the unparalleled catastrophe left humanitarian instincts, or the rudimentary disaster-assistance machinery of the UN, untouched. To date some US$40 million worth of help, about half of it from the United States, has been made available for relief use under UN auspices.

But, in the wake of Indian Foreign Minister Swaran Singh's visit to the UN's headquarters, and judging by the many thousands of words flooding out of the Indian and Pakistani missions here, it is quite clear that no amount of humanitarian help will ever cope with the problem unless there is a political solution. And it is evident also that failing considerable great-power pressures on the Pakistani government - through the UN system or independent of it - there is going to be no decisive effort to achieve a political resolution. Lack of one will promote the further exodus of millions of Bengalis and Hindus from East Pakistan into overcrowded India, bringing closer the frightful spectre of another war between Pakistanis and Indians.

India's main point, said Singh, meeting the press after his talk with UN Secretary General U Thant, is that the tragedy which has befallen East Pakistan is a great international matter, and whatever India is doing to alleviate the sufferings of the East Bengalis fleeing from the West Pakistani military is done "on behalf of the international community".

Put in other words, the Indian contention is that the East Pakistani events constitute a danger to international peace. This is the message India's foreign minister carried to Moscow, Bonn, Paris, Ottawa, Washington, the UN and London - so far, apparently, to no avail. Had he succeeded, the UN Security Council would already have met to discuss the problem: a threat to international security is the very thing which, in the language of the UN Charter, must trigger such a meeting .

When asked if he contemplated a call for security council action, Singh was evasive. "It is up to the security council to take note of events," he said, adding "it is the secretary general who could make the move." His response showed he was well aware of the basic dilemma: the great powers do not wish to be put on the spot over Indo-Pakistan relations in any public meeting of the security council. That was the sad message which greeted the Indian foreign minister in the capitals he visited.

The Indians charge that the whole East Pakistani tragedy was caused on purpose by West Pakistan which, New Delhi claims wants to disrupt the Indian economy, cause fratricidal conflicts in the poor states now absorbing the paralysing flow of millions of refugees, and general chaos throughout India and all on behalf of Peking.

Pakistanis here, including Ambassador Agha Shahi, dismissed Singh's case indignantly but not entirely convincingly. They pointed out that a general amnesty had been declared and over 20 reception centres set up - though they did not say how well they had been filed by returning refugees. They also said Pakistan had asked UN High Commissioner for Refugees Prince Sadruddin Aga Khan to visit refugees in India and work out a means of mass repatriation. The prince's verdict was not perhaps what they had hoped, since though he claimed conditions in East Pakistan were improving, he firmly denied reports that he had said conditions were satisfactory for the refugees to return, or that the UN could guarantee their safety.

Pakistan claims New Delhi is deliberately scaring the refugees to prevent them returning home a charge which, considering the frightening cost to India of their presence in India, needs to be proved. Singh's clear warning later in Washington that the refugee influx threatened "to engulf our region in a conflict the end of which it is not easy to predict" may have been a bid to get Washington moving in the political field. But it also reflects a genuine possibility.

Far from the scene, observers here and in Washington are in no position to know the truth. But what is obvious is that the great powers which could put on the pressures needed to end the tragedy are shying from the task because none is willing to offend either New Delhi or Islamabad.

Meanwhile cholera, gastro-enteritis and starvation govern East Pakistan. And India faces problems which, as Premier Indira Gandhi eloquently pointed out last weekend, the outside world had provided only a tenth of the wherewithal to meet. In the UN's air-conditioned headquarters in New York, hearts may bleed but political wisdom counsels "restraint".