Chinese leader Deng Xiaoping has offered Taiwan qualified independence as a local government but insisted that only the Communist regime here has the right to represent China in the international arena, the state-run news agency reported tonight.

At the same time, Deng took a verbal slap at President Reagan, whose arms sales to Taiwan are regarded by Peking as the chief obstacle to reunification. He accused Reagan of fickleness in his Taiwan policy, contending that "our policies are far more stable than those of the United States."

"The United States has lauded its system to the skies," said Deng. "But a president says one thing during the campaign, another when he takes office, another during the mid-term election, and still another near the next general election."

Deng's remarks were made during an extraordinary meeting held here June 26 between the Chinese leader and Prof. Winston Yang of Seton Hall University. Yang, born in China and reared in Taiwan, held a two-hour talk with Deng that focused on the question of China's reunification with Taiwan. Yang's disclosure this week of the content of the discussion apparently prompted the Chinese official news agency to rush an official, though incomplete, text of the talks into print.

During an interview Friday in Washington, Yang said that Deng offered a number of new proposals to open a dialogue with the Taiwan government on reunification. According to Yang, Deng pledged that China "will not send troops or officials to Taiwan to take over, to manage to supervise or to interfere with Taiwan's internal affairs" during a 100-year-long transition to complete reunfication. Yang quoted Deng as saying, "Taiwan will retain its own armed forces and also has the right to acquire weapons to maintain defense capabilities."

[In a symbolic yet significant change in policy, Deng reportedly said that "Taiwan may use its own flag and use the name 'China, Taiwan.' " Until now, China had insisted that reunification would require Taiwan to fly the mainland flag and refer to itself as "Taiwan, People's Republic of China." According to Yang, the plan would "essentially maintain the status quo and will only give the appearance of reunification." In terms of internal affairs, Taiwan would be independent under Deng's new reunfication plan, Tang said.]

Taiwan, a capitalist island of 18 million people, has been ruled by the Chinese Nationalist Party since it lost control of the mainland in 1949 and fled from the Communist takeover. The Nationalists had U.S. recognition until 1979 and continue to buy almost all their military supplies from the United States.

Peking threatened to forcefully "liberate" Taiwan until adopting a policy of "peaceful reunification" in 1979 when Washington recognized the Communists as the sole, legal government of China. Deng's June 26 remarks are the most explicit outline of Taiwan's would-be status in a reunified state since Peking made its initial 9-point proposal in September 1981.

The Nationalists have rejected the proposal as a trick to open the way for Communist seizure and repression, saying they would only consider reunifying with Peking if it abandoned communism and embraced Nationalist political principles.

"We mean what we say," Deng said in his official remarks. "We play no tricks."

Deng, China's foremost political figure, called Taipei's demands "unrealistic," offering instead Peking's plans for turning the island into a special administrative region with "exclusive rights" to administer its legislative, judicial and military systems without interference from the mainland government.

In this fashion, he said, Taiwan could retain its "independent nature and practice a system different from that of the mainland. It may exercise independent jurisdiction and the right of final judgment need not reside in Peking."

"Peaceful reunification does not mean the mainland swallowing up Taiwan, of course, nor vice versa," he added.

Although his offer is the most far-reaching in assuring the nationalists a free hand in running their island, Deng emphasized that any autonomy would be limited and conditional.

As for "exclusive rights" that would be enjoyed by Taipei--he apparently was referring to the ability to retain an armed forces and foreign economic and cultural relations--he added an important qualification: "on the condition they do not impair the interests of a unified state."

He said Taiwan could keep its armed forces, "so long as they do not constitute a threat to the mainland."

"Complete autonomy is simply out of the question," he told Yang. "Complete autonomy means 'two Chinas,' not 'one China.' "

In his Washington remarks, Yang said that "Deng didn't specify, but my thinking is that Taiwan can buy weapons from foreign countries (but) Taiwan cannot enter into (military) relationships with foreign countries." These remarks are seen as aimed at easing Taiwan's fear that any move toward reunification would leave it defenseless against a mainland invasion.

On the controversial question of foreign affairs, Yang quoted Deng as saying that "Taiwan will maintain independent economic relations with foreign countries and Taiwan will issue visas to foreign visitiors and issue passports." However, Yang said that major policy differences between Tawian and China "have to be worked out" because the transition to full reunification "has to be done under the principle of one China." And yet, according to Yang, Deng said "The mainland will continue its socialist system while Taiwan may continue its capitalism."

[Yang stressed that the Chinese leader does not believe the new plan will lead to any diplomatic breakthroughs, and expected the Taipei authorities to reject it immediately. "It's no surprise Taiwan reacts with its standard phrase," Yang said. "Taiwan is in a difficult position." Yang said Deng hopes the new proposals will initiate a dialogue between the two countries that could lead to more earnest talks. "Depending on circumstances, things may go further," Yang said.]