New Delhi: Bangla Desh's real problems will start only after the last Pakistani soldier there has been accounted for. While Sheikh Mujibur Rahman remains the hero of Bengal, his absence from the scene will pose political problems for the Awami League. Besides, it is fully realised on all sides that the independence of Bangla Desh has been achieved not so much by the electoral victory of the Awami League as through the sacrifices of the freedom fighters. The Mukti Bahini ranks include volunteers of all political persuasions.

Some of them already have staked their claims for representation in the new government in Dacca (which, incidentally, is likely to be renamed Mujibnagar). Acting President Syed Nazrul Islam and Prime Minister Tajuddin Ahmed drove triumphantly into Jessore last Saturday to assure wildly cheering crowds that Bangla Desh soon would have a constitution - unlike Pakistan, which has had none in its 25-year history. They proclaimed that it would be a republican constitution based on secularism and non-alignment and safeguarding the rights of minorities.

Finance Minister Mansoor Ali said the new country's economic policy would be based on the socialistic pattern as in India. Whatever wrangles may develop for power in the new country, all are now agreed that Bangla Desh must cooperate fully with India, that the two must work together as good neighbours. Indian Prime Minister Indira. Gandhi backed up this sentiment by publicly declaring in New Delhi last week that India would not interfere in the internal affairs of Bangla Desh but would strive to demonstrate to the world how two good neighbours could work together and contribute to mutual prosperity.

As the Indian troops began their assault on Dacca, an agreement was signed between Mrs. Gandhi and the Bangla Desh leaders spelling out the immediate role of the Indian Army, the Mukti Bahini and the civil servants of the two countries.

One immediate problem India will have to tackle is what to do with the arms captured from Pakistani forces. Indian commentators have pointed out that the Indian Army wasted a great deal of time with minor towns and garrisons instead of going for Dacca at the outset.

This, they said, was because the Indian Army wanted to take possession of Pakistani arms and ammunition and prevent them falling into the hands of local groups who could some day use them to subvert the new state; some Maoists are believed to have infiltrated the Mukti Bahini. India's view is that if the captured arms are not properly secured they might fall into the wrong hands, creating new problems not only for the new state but for India, whose West Bengal has its own law-and- order problems .

The priority issues facing Bangla Desh already have been spotted. The first is repatriation of refugees: some 60,000 had already gone home from Tripura and Assam by December 10. After this comes restoration of war- shattered road, rail and telecommunication lines followed by resumption of industrial production, restoration of law and order with special attention to the safety of minorities, and restoration of property wrongly seized by the army.

Tajuddin Ahmed has said war criminals and collaborators will be tried. India is expected to counsel a "forgive and forget" policy. The Mukti Bahini has been persuaded by the Indian Army to treat fairly those who surrender to them.

It is believed that the restoration of the civil administration will not be too difficult. Many Bengali officers reported for duty as soon as an area was liberated. India has offered the services of some senior officials to help plan the 1 tougher job of building new bridges and f setting up a new communication net-: work. Some 25 officials already have been seconded from West Bengal.

For her part, Mrs. Gandhi will depend on three or four advisers to formulate z her policies on Bangla Desh. One, of course, will be Durga Prasad Dhar, who is in overall charge of policy. Among others with intimate knowledge of Bangla Desh problems are former Cabinet ministers Triguna Sen and A. K. Sen - both Bengalis - and Gulzarilal Nanda, who has been active in helping the Mukti Buhini.

An interesting aspect of the new situation is that religion-based politics will now receive a setback in the subcontinent. Pakistan has been at loggerheads with India in the name of Islam. Now the balance of population has tilted; the 65 million Muslims in India and an equal number of Muslims in Bangla Desh together outnumber the 60 million Muslims of Pakistan. If Bangla Desh and India live in friendship, tolerating all religions, Pakistan will find it difficult to raise the "hold war" cry in future.