TAIPEI, Apr. 25 -- The Taiwanese opposition leader's plans to visit China have won the last-minute blessing of Taiwan's president, who once warned it could bring treason charges but now sees it as a way to test the mainland's willingness for reconciliation.

During the weeklong trip starting Tuesday, Nationalist Party Chairman Lien Chan will meet with Chinese President Hu Jintao in the first top-level meeting between the Nationalists and Communists since 1949, when Gen. Chiang Kai-shek fled the mainland after losing a war to Mao Zedong's guerrillas.

Lien, whose party favors friendlier ties with China, has said he would make the journey as a private citizen but hopes to lay the groundwork for improved relations and closer trade links with the mainland.

The trip marks a formal thaw between the Communists and Nationalists, who ruled Taiwan for half a century before losing the presidency in 2000.

It might also foster reconciliation between China and Taiwan, whose political disputes have turned the Taiwan Strait into one of the most dangerous flashpoints in Asia.

President Chen Shui-bian earlier warned Lien against playing into the hands of the communists and threatened to charge him of treason if he signs any deals without government authorization.

But Chen softened his stance over the weekend and said Lien could use the journey to "toss a stone to test the water" of reconciliation.

China still claims that self-ruled Taiwan is part of its territory and says the island could face a war if it makes its de facto independence permanent.

Taiwan's president has confronted Beijing with harsh rhetoric and fiercely resisted its efforts to unite the island the mainland. China reacted by passing an anti-secession law last month that authorizes an attack to stop the island from moving toward formal independence. Taiwanese officials said Lien's trip is ill-timed and could encourage China's militancy toward the island.

But many Taiwanese support moves to ease the simmering tensions and want the two main political parties to come up with a concerted China policy.

The respected Journalist weekly praised Lien for "taking the initiative to make the first stride of ... using goodwill to bring forward more goodwill and end a cycle of triggering malice with malice."

"China has hoped to nurture a peaceful environment for its development and it needs Taiwan's help at this moment. Taiwan's role shift will sure win gratitude from the Chinese. The two sides can hold hands to rewrite history," it said.

Lien's April 26-May 3 trip will include visits to the grave of Nationalist Party founder Sun Yat-sen in Nanjing and Lien's birthplace in Xi'an.