The president's chief trade negotiator and top officials of the textile and apparel industry reportedly reached a tentative agreement yesterday aimed at averting a protectionist fight in Congress that could wreck chances for a new international trade pact.

The agreement, which apparently assures the import-threatened industry of government help in meeting a variety of domestic and foreign trade problems, is subject to consultations within the Carter administration and Congress, sources said.

Yesterday's meeting in New York was the latest in a series of private sessions between Robert S. Strauss, the president's special trade negotiator, and industry leaders, including union officials, to resolve their potentially explosive differences on trade matters before the trade pact goes to Congress.

The industry's position is crucial because of administration fears that the multinational trade talks nearing completion in Geneva could collapse if the industry succeeds again in getting Congress to exclude textiles from any tariff cuts in Geneva.

Such an exclusion passed Congress last year but was vetoed by President Carter. A new version of the taxtile exemption has been introduced in the House and Senate.

Moreover, the administration is pushing for prompt congressional action on an extension of a waiver, which expired Jan. 3, that permitted the United States to refrain from imposing countervailing duties on subsidized imports until the new international trade agreement is completed. The textile exemption could be added to the waiver measure, which other countries have demanded as the price for completing an overall trade agreement. "That would be almost a death knell for the negotiations," Strauss said recently in speaking of the proposed textile exemption.

The latest round of Geneva trade talks among nearly 100 nations is aimed not only at tariff reductions but also at partial or total dismantling of such nontariff barriers to trade as export subsidies, government procurement practices and product standards. The nontariff matters are the focus of the negotiations, although the textile tariffs have become an early stumbling block.

In vetoing the taxtile exemption last year, Carter listed a number of steps the government might take in reaching a quid-pro-quo agreement with the textile and apparel industry. These included review of bilateral agreements covering textile imports, some restraints on textile imports from the People's Republic of China and government efforts to promote competitiveness for U.S. textile exports.

Sources indicated Strauss' talks with textile industry officials were proceeding along these lines. Meanwhile, the government has moved quickly to set up talks with Chinese officials on textile trade, with meetings to start next week.

Without spelling out details, Murray Finley, president of the Amalgamated Clothing and Textile Workers Union and a participant in yesterday's talks with Strauss, said Strauss will soon be drafting a "position paper" on the government's plans and circulating it in the executive and legislative branches.

"The Carter administration is trying to live up to its promises to deal concretely and effectively with problems of the textile and apparel industries and unions," said Finley, who had previously joined in industry criticism of the administration's trade practices.