Foreign Minister Sahabzada Yaqub Khan of Pakistan arrived here today for three days of meetings with Indian officials in an effort to improve relations between the two neighboring nations. Those ties appear to have turned sour because of heightened Indian concerns that Pakistan is on the verge of exploding a nuclear weapon.

Although Yaqub Khan was here in April for a gathering of the Nonaligned Movement, this is the first ministerial-level session of a joint Indo-Pakistani commission in two years.

The 1984 meeting was canceled by India as a sign of its anger over what New Delhi felt was a campaign against it in Pakistan over India's actions against Sikhs in the Punjab, especially the storming by the Indian Army a year ago of the sacred Golden Temple in Amritsar.

The resumption of talks is seen here as an indication that the two countries want to make an effort to improve relations, despite the strains.

As tempers appeared to have cooled on the Punjab issue, India has raised the volume in recent months over what it sees as Pakisan's push to build nuclear weapons.

Prime Minister Rajiv Gandhi brought up Pakistan's nuclear program when he met in Washington last month with President Reagan and received assurances that the United States also opposes Pakistan developing nuclear weapons. For its part, Pakistan steadfastly has denied its nuclear program is aimed at building weapons, insisting it only has peaceful purposes.

While the nuclear issue is unlikely to come up in the formal session of the commission, it may surface in Yaqub Khan's private meetings with Gandhi and other top Indian policy makers.

Pakistan's four-year-old offer of a no-war pact and India's counterproposal of a treaty of peace and friendship also are unlikely to be part of the formal discussions here. The two foreign secretaries, India's Romesh Bhandari and Pakistan's Niaz Naik, will take up those issues at a special meeting July 30.