Chinese Ambassador Chai Zemin was called to the State Department yesterday as part of the effort to resolve the dispute between the two countries over the continuing U.S. supply of arms to Taiwan.

Chai, who saw Secretary of State Alexander M. Haig Jr. for 30 minutes and Assistant Secretary of State John H. Holdridge for 90 minutes, told reporters afterwards that he had held "informal" discussions on issues that are under formal negotiation in Peking.

State Department spokesman Dean Fischer declined to say whether the administration has set a date for the transmission to Congress of a planned sale of military spare parts to Taiwan. The dispatch of such a proposal in present circumstances could bring a sharp Chinese reaction, possibly including the withdrawal of Chai and the expulsion of the U.S. ambassador to Peking, in the view of some China-watchers here.

Key members of Congress recently were informed that the administration plans to send the long-delayed Taiwan arms sale package to Capitol Hill within a few weeks.

A senior State Department official said late yesterday that the administration remains hopeful that a political accord over the issue can be worked out with China, though he conceded that many difficulties remain.