Taiwan leader Chen Shui-bian has given his "blessing" to this week's landmark mainland visit by the island's major opposition leader, reversing earlier criticism of the trip, a senior Taiwan official said.

Chen had repeatedly accused Kuomintang (KMT) leader Lien Chan of being the mainland’s promotional tool.

Another opposition leader James Soong, chairman of the People First Party, has also accepted Beijing's invitation to visit the Chinese mainland. A group of officials from Soong's party flew to Beijing Sunday to discuss the arrangements for the trip.

While addressing party members in Taipei on Saturday, Chen said the law does not bar the pair from traveling to the mainland.

"In the past, the two sides did not have direct contacts," he was quoted as saying by“Presidential Office”press secretary Chen Wen-tsung in interview with AFP.

"Now Lien and Soong will have the chance of talking with Chinese leaders directly and therefore providing us with first-hand information," Chen Shui-bian said.

"We could regard the visits as 'stones to be thrown to explore the roads ahead' and give them our blessing," Chen added.

Lien is due to begin his eight-day "peace journey" Tuesday during which he will travel to Nanjing, Beijing, his birthplace Xi’an and Shanghai. He is scheduled to meet President Hu Jintao, also the general secretary of the Chinese Communist Party, in Beijing on Friday.

Analysts said Chen's public U-turn over the visits came about as a result of pressure from Washington, which has repeatedly called on Taipei and Beijing to settle their dispute peacefully through dialogue.

KMT spokesman Chang Jung-kung told reporters he was informed by Washington's de facto envoy to Taipei, Douglas Paal, that the United States supports Lien's China visit as it could help ease Taipei-Beijing tensions.

President Chen warned the duo not to sign any agreement with Beijing without Taipei's official approval.

"The government's position is crystal clear. It's fine if Lien and Soong want to travel to China either for sight-seeing or for tomb-sweeping purposes," he was quoted as saying by his spokesman. "But whenever they talk with the other side involving the government's authority, then they will need the government's authorization," he said.