Beijing's representative Chen Yunlin and his local counterpart Chiang Pin-kung shook hands as they took their seats at Taipei's Grand Hotel for the discussions that are expected to ink deals potentially worth billions of dollars.

"Now we are very close to agreement, and I hope we will reach a consensus this afternoon on shipping, air transport, postal services and food security," said Chiang, who head's Taiwan's Straits Exchange Foundation.

Late Monday the two sides announced they had agreed to triple direct passenger flights across the Taiwan Strait that separates the island from China to 108 per week and expand services to 21 more Chinese cities.

Chen, head of China's Association for Relations Across the Taiwan Strait, told Tuesday's talks opening, which was broadcast live on television, that the dialogue would build on progress made in June in thawing the relationship between the former arch foes.

"In June the two sides signed agreements which opened a new page in the relationship and marked a milestone in the development of cross-strait ties," he said.

"We will make our best efforts to satisfy the needs of the Taiwanese people on a mutually beneficial basis."

He said the agreements "will promote civil exchanges, economic cooperation to enhance the welfare of the people on both sides".

The deals are expected to be signed by both parties Tuesday afternoon.

Aside from the four main issues, Chen has said that boosting tourism would also be discussed. The June talks agreed a daily quota of 3,000 Chinese tourists to Taiwan, but China still restricts travel to the island.

Opponents of the deals have warned of a Chinese stealth takeover of the island, which has been estranged from China since the end of a civil war in 1949, in which Mao Zedong's Communists vanquished the nationalist Kuomintang (KMT) forces.

Chen became the most senior Chinese official to visit the island in almost 60 years when he arrived Monday for a five-day visit, marked my massive security and widespread protests against closer ties with Beijing.

Relations between the two sides have been on an upward trajectory in the months since the KMT's Ma Ying-jeou became president, ending eight years of rule by the pro-independence Democratic Progressive Party (DPP).

DPP supporters oppose Chen's visit and have accused Ma of undermining the island's sovereignty in its efforts to move closer to China.

"We are concerned that Taiwan is gradually losing out its sovereignty after the interactions with China," the party's chairwoman Tsai Ing-wen said Monday.

Chen is expected to meet President Ma on Thursday, in one of the contentious appointments in his schedule.

DPP officials have said that how Chen addresses Ma -- as "president" or simply "mister" -- will send a clear message of Beijing's intentions towards the island, which it regards as a renegade province to be reunited, by force if necessary.

Despite assurances that political issues will not be discussed this week, local television has said that Ma could ask that Beijing remove missiles -- believed to number up to 1,000 -- targeting the island.