Mr Chen Yunlin, chairman of China's semi-official Association for Relations Across the Taiwan Strait (Arats), will travel to Taipei on Monday for a five-day visit.

He will represent Beijing in the second round of cross-strait talks during which several agreements are expected to be inked, including air cargo services and expanding direct air and sea links.

The first round of talks were held in Beijing in June after a 10-year hiatus.

The date of Mr Chen's visit was finalised yesterday after officials from both sides sat down for preparatory talks in the southern Chinese boomtown of Shenzhen. But his itinerary was not immediately available.

The Chinese envoy is expected to hold talks with his Taiwan counterpart Chiang Ping-kung next Tuesday while their deputies meet to finalise agreements to be signed the next day at Taipei's Grand Hotel, according to the Taiwanese press. A highlight of the trip would be a likely meeting between the Chinese envoy and Taiwan President Ma Ying-jeou.

Attention in Taipei has focused on whether Mr Ma would introduce himself as the President of the Republic of China - Taiwan's formal title - during the meeting.

China and Taiwan split amid civil war in 1949, but Beijing continues to claim the island as part of its territory.

Mr Chen will be the most senior Chinese official to set foot in Taiwan since 1949. But recent protests in Taiwan have threatened to overshadow the closely watched visit.

Over the weekend, hundreds of thousands of people took to the streets of Taipei to denounce the government's strengthening ties with Beijing, which they claim threaten the sovereignty of the self-ruled island.

The opposition Democratic Progressive Party (DPP), which organised the rally, claimed that up to 600,000 people took part in the biggest demonstration since Mr Ma of the China-friendly Kuomintang (KMT) took office in May. Police in the capital put the turnout at around 180,000.

Last week, demonstrators in the southern Taiwan city of Tainan pushed to the ground Mr Chen's deputy who had travelled there for an academic conference, outraging Beijing.

Yesterday, Taiwan's top China policymaker defended the upcoming talks and pledged that any deal with the mainland would be transparent and would not jeopardise the island's sovereignty. Mainland Affairs Council chairman Lai Shin-yuan said the KMT government would not forge any secret deals with China during the talks.

'Once agreements are signed, I will report to the Legislative Yuan (Taiwan's Parliament). Everything can be examined in broad daylight,' Ms Lai told reporters.

In a bid to improve the atmosphere ahead of Mr Chen's visit, China yesterday apologised to Taiwan over tainted Chinese milk products that sickened three children and a woman on the island, another major cause of the weekend's rally.

'The incident has caused troubles and losses to Taiwanese consumers and companies, and we apologise to them,' Arats said in a rare letter of apology. Taiwan banned Chinese dairy products when the milk powder scandal surfaced last month.

But the DPP yesterday poured cold water over Beijing's gesture.

Reports said DPP leaders were planning a fresh wave of street protests to coincide with Mr Chen's visit.

About 7,000 police officers would be ready to handle any upsets, Taiwan's National Police Agency director-general Wang Cho-chiun told reporters yesterday.

Mr Chen's deputy, Mr Zheng Lizhong, told a televised news conference yesterday that Taiwan has promised to ensure the envoy's 'safety and dignity' during the five-day visit.

ASSOCIATED PRESS, AGENCE FRANCE-PRESSE, REUTERS