Pakistan's growing anxiety over the Soviet military presence in Afghanistan and the potential for cross-border subversion has dramatically affected its attitudes toward India, and has presented an opportunity for a new strategic equation in the Subcontinent, a senior U.S. official said today.

The official, speaking with reporters during a visit to the region by a U.S. delegation headed by Undersecretary of State for Political Affairs Lawrence Eagleburger, said that the Indian government of Prime Minister Indira Gandhi does not yet appear ready to take advantage of the opportunity for a new alignment by openly acknowledging the danger of continued Soviet Army intervention in Afghanistan.

Moreover, it is unlikely that India's position will change significantly as it prepares to host the seventh summit conference of nonaligned nations in March, the senior official said.

As India assumes the chairmanship of the Nonaligned Movement from Cuba, it is likely to adhere more than ever to its detached posture on the Afghanistan question, at least until a consensus on the issue is reached within the movement, he said.

The assessment came as the high-level State Department team completed a round of talks in Islamabad and here in the Indian capital. Eagleburger was accompanied by Deputy Assistant Secretary Howard Shaffer and Geoffrey Kemp of the National Security Council.

After a series of meetings in Islamabad to prepare for President Mohammed Zia ul-Haq's scheduled state visit to Washington Dec. 6, the group met here with senior officials of the Indian Ministry of External Affairs.

During Gandhi's meetings with President Reagan last July, the two leaders decided to renew regular political consultations on major bilateral and international issues after a three-year lapse.

The senior U.S. official said a recent thawing of relations between India and Pakistan, as evidenced by Zia's meetings with Gandhi during a brief stopover here Nov. 1, was "not just theater."

Meeting for the first time on the Subcontinent, Zia and Gandhi agreed to establish a joint commission to begin talks on a nonaggression pact that Pakistan first suggested in September 1981, and the friendship treaty that India offered this September.

"Afghanistan has made a tremendous difference in their [the Pakistanis'] attitude. Their problems in the East, in a military sense, have shifted westward," said the U.S. official, who asked not to be identified.

"That doesn't mean that peace has broken out in all aspects . . . but Mrs. Gandhi recognizes on the Indian part that this is an extremely difficult time for Pakistan, and she apparently wants to show some understanding. There seems to be some sympathy with the Pakistanis' concern over Afghanistan," he said.

However, the official added that "if one wanted to, one could take real advantage of the situation. But they the Indians have not. They have not recognized that their interest is not served by the continuing Soviet presence in Afghanistan."

India has abstained on three U.N. resolutions condemning the Soviet intervention in Afghanistan. Gandhi, while saying she would prefer to see the estimated 100,000 Soviet troops leave, also has stressed that as long as outside support of the insurgents continues, conditions will not be conducive to a Soviet withdrawal.

The Soviet Union, which in 1971 signed a 20-year mutual defense treaty with India, is India's major arms supplier and trading partner.