New Delhi — The first visit of a Pakistani leader to New Delhi in a decade signals a subtle easing of tensions in South Asia.
Pakistan's President Mohammed Zia ul-Hag has been wanting to visit India since seizing power over five years ago in a military coup. On previous occasions Indian Prime Minister Indira Gandhi has politely, but firmly, demurred.
Now, however, it is in the interest of both Pakistan and India to seek a rapprochement.
President Zia's meeting Nov. 1 with Mrs. Gandhi could prove more important than the other stops on his Asian tour to Malaysia, Indonesia, and Singapore. A warming of relations between the two countries would come after countless border skirmishes and three major wars since the partition of British India 35 years ago.
Subtle shifts in the region's alignment of powers are already taking place. Mrs. Gandhi has begun delicately distancing herself from Moscow, and is no longer so outspoken in her rationalization of the Soviet invasion of Afghanistan.
She has also embarked on a new dialogue with China which, along with the United States, has stood firmly at the side of Pakistan.
As for President Zia, he has argued that the presence of Soviet troops in Afghanistan makes Pakistan a ''frontline'' state against the Soviet Union. Last November he offered a no-war pact to India. New Delhi responded with a counter-proposal of its own - a friendship treaty, and the establishment of a joint commission to normalize relations in all fields.
The three proposals are still on the table and, it could take more than one India-Pakistani summit meeting before negotiations go much further.
Beyond the bilateral issues, both sides realize that there will be a new spotlight on South Asia beginning in March 1983 when India assumes the chairmanship of the conference of nonaligned states.
''There is nothing about Mrs. Gandhi that is left to chance,'' said one Indian official. ''She watched (Cuba's Fidel) Castro lose the nonaligned mantle because of his pro-Soviet stand. She knows that China commands nonaligned votes in Africa and Asia. Zia could help her here. And there have always been those around her who have realized that India and Pakistan have a common interest in curtailing Soviet encroachment. . . . She's spent a lot of time intellectualizing the invasion of Afghanistan. She never before saw the Soviet Union as a threat to Indian security. But that was before the Soviets were in the Khyber pass.''
Following a visit to China earlier this month, Zia called for an international conference on Afghanistan, to include Pakistan, China, Iran, the Afghan guerrillas, the Soviet Union, and the United States. In some ways, Afghanistan is the least contentious issue dividing the two leaders, as neither is directly involved in the fight against Soviet troops.
Conversely, on the long-standing border issue of Kashmir, over which their nations have fought two costly wars, the two leaders are not expected to come to an easy or quick agreement.
President Zia cannot help but remember the Pakistani Army's humiliating defeat at the hands of Mrs. Gandhi's forces 11 years ago. Since then, there has been a sizeable military build-up of the two countries.
Pakistan has just signed an agreement for the delivery of 40 sophisticated F- 16 fighters from the United States. India will receive from France an equal number of the Mirage 2000 fighters and Exocet missiles of Falkland Islands fame.
Although both leaders have said publicly that they have no objection to the arms build-up on the other side, Mrs. Gandhi is almost certain to raise the contentious issue of Pakistan's nuclear capability.