Taiwan President Chen Shui-bian has urged the Chinese government to open talks with his administration.
Lien Chan paid his respects at his grandmother's grave
The call comes as Taiwanese opposition leader, Lien Chan, continues a visit to China, where he has held historic talks with President Hu Jintao.
Mr Chen said Beijing had to talk to the leader chosen by the people of Taiwan, and he was sending a personal message to Mr Hu through an envoy.
Mr Lien heads the KMT, who were driven out by the Communists in 1949.
The leader of the smaller opposition People First Party, James Soong, is also due in the mainland for talks this week. President Chen has asked him to take his undisclosed message to leaders in Beijing.
The Taiwanese president favours formal independence from China, whereas Beijing regards Taiwan as a renegade province.
The nationalist Kuomintang (KMT) has previously said it favours eventual reunification, so long as China is by then democratic.
The People First Party also favours Taiwan's eventual unification with mainland China.
Beijing's strategy has been to reach out to Taiwan's opposition politicians, in a bid to isolate Mr Chen and force him to moderate his pro-independence stance, says the BBC's Louisa Lim in Beijing.
But big obstacles still remain to cross-straits ties, our correspondent says.
China refuses to talk to Mr Chen until he signs up to their one-China policy - something which would be political anathema for him, she says.
Lien Chan has been feted by massive crowds as he continues his trip to China. Thousands turned up to greet him as he paid his respects at his grandmothers' graveside in Xian, where he was born before World War II.
The crowds in Xian waved the flags of both communist China and the nationalist Kuomintang party which fled to Taiwan in defeat in 1949.
Ruled by separate governments since end of Chinese civil war in 1949
China considers the island part of its territory
China has offered a "one country, two systems" solution, like Hong Kong
Most people in Taiwan support status quo
"To come here today is very moving," Mr Lien said.
Mr Lien is being treated like a head of state, with lavish receptions everywhere he goes, a sign that Beijing's happy with the momentum created by his visit, our Beijing correspondent says.
But President Chen said: "Regardless which political party or leader China wants to meet, eventually it must talk with Taiwan's popularly elected leader and the Taiwan government, and this will be the normal dialogue to start normalization of relations."
Mr Lien and his family moved to Taiwan in 1946, while the civil war was still raging.
The next stop on his mainland tour will be Shanghai, which has seen large-scale Taiwanese investment.