The first talks between senior members of the Indian and Pakistan governments in six years opened here yesterday morning in an atmosphere of uprecedented cordiality.

The Indian foreign affairs minister, Atal Bihari Vajpayee, who is here for a three-day visit, met both his Pakistan opposite number, Agha Shahi, and the military ruler, Gen. Zia ul-Haq. Both sides later talked expansively of possibilities for "improving" and perhaps even "normalizing" relations between the traditionally hostile nieghbor nations.

Zia was in a particularly optimistic mood. "There are only two problems between our two countries," he said. "No. 1 - Kashmir. No. 2 - the misconceptions we have of one another. Solve those and we can go as far as we like."

Vajpayee, who is perhaps a more cautious politician, was more curcumspect. Kashmir had been discussed in the hour-long talks with Shahi, he confirmed, as had other "bilateral matters."

So far as firm results are concerned, it looks as though little will be announced in Wednesday's closing communique beyond general expressions of good will. Zia has been invited to New Delhi Vajpayee carried with him a personal letter from Morarji Desai, the Indian prime minister - and he will probably go in March or early April. There may be an agreement to permit more exchanges of reporters, athletes and others.

There also may be agreement on remedying the trade imbalance between the two countries - India sells about $30 million worth of goods annually to Pakistan, with less than $2 million going in the other direction. But neither officials directly involved nor interested diplomatic observers expect much more.

Yet, the real importance of the visit is that it has happened at all, and that it is Vajpayee, a man whose party background in India has been especially hostile to Pakistan, is leading it. Zia said last night that he felt, despite his avowed intention to remain only an "interim" leader of Pakistan, that he had a mandate to negotiate with India. "No government can afford to stand still in matters like these. I am doing this in the interests of the country, and everyone should realize that."

Vajpayee was accompanied by some 20 Indian journalists, who have been allowed in on five-day visas. There were touching scenes at the airport, and at various press functions later in the day, as the visitors met colleagues, friends and even relations from whom they have been divided, by the border, and the three wars that have been fought across it, for 30 years.

Some were greed by an elderly Pakistani customs official, who had been born and brought up in what is now Uttar Pradesh, in India. A Moslem, he had fled here in 1947.His father had died in Lucknow four years ago, he said, and he had not been allowed to cross to India for the funeral.He hoped - and his old eyes filled with tears as he said so - that the talks now and later in the spring would ensure that such visits might one day become commonplace.