The mainland visit of a senior member of Taiwan's main opposition party has raised expectations for better exchanges between the mainland and the island's Democratic Progressive Party.

Chen Chu, mayor of Kaohsiung, arrived in the mainland on Friday and is staying until Wednesday.

Yang Yi, spokesman of the State Council's Taiwan Affairs Office, told Xinhua News Agency that the mainland always supports city-to-city exchanges across the Taiwan Straits, and also welcomes people from Taiwan "as long as they endorse the idea of cross-Straits peaceful development", he said.

But the DPP's policy "remains unchanged", and inter-party communication will be impossible if the DPP doesn't change its pro-independence stance, Yang said.

Chen arrived in Shenzhen on Sunday after a weekend stay in Tianjin. She is also scheduled to visit Xiamen and Fuzhou in Fujian province.

It is Chen's second visit to the mainland. She came to promote the Kaohsiung-hosted World Games in 2009, which made her the highest-ranking member of the DPP who has ever visited the mainland.

Chen is one of the founders of the DPP and was its acting chairwoman following the resignation of Tsai Ing-wen after the DPP's loss of the Taiwan leadership election to the ruling Kuomintang in January 2012.

Her relations with Beijing soured when she met the Dalai Lama in Kaohsiung in 2009.

Chen said the goal of her visit is to invite mainland cities to attend a conference of mayors that will be in Kaohsiung in September and to promote intercity exchanges.

Chen met the mainland's top official on Taiwan affairs, Zhang Zhijun, during her stay in Tianjin.

Zhang, head of the State Council's Taiwan Affairs Office, said the mainland welcomes and encourages people from various Taiwan political parties and mayors to participate in the peaceful development of cross-Straits relations.

Zhang and Chen exchanged ideas on promoting peaceful development of cross-Straits relations and boosting exchanges between cities across the Straits, Xinhua News Agency reported.

Zhang reaffirmed the mainland's stance of supporting exchanges between cities across the Straits, while Chen said she looks forward to more exchanges, Hong Kong-based Phoenix TV reported.

While in Tianjin, Chen also visited the city's urban planning exhibition center and a cruise terminal. She said she will be happy to see cooperation between Kaohsiung and Tianjin, both of which are port cities that have harbor construction and cruise tourism.

Although the 63-year-old Chen has played down the political implications of her trip, experts said she has expressed goodwill to the mainland, and her political influence in the DPP is likely to encourage more local leaders of her party to visit the mainland as well.

Wang Hailiang, a researcher from the Shanghai-based Taiwan Research Institute, said cross-Straits communication on trade and culture has become a major topic on the island, and the DPP is losing its say on related issues due to its absence in mutual exchanges with the mainland.

"The party hopes it can offer voters a brand-new vision with the mainland, ahead of upcoming mayoral elections next year and a new round of leadership elections in 2016," he said.

The mainland's sincerity, Wang said, could be seen in Chen's meeting with Zhang, the mainland's top official on Taiwan affairs. It was an arrangement "not commonly seen in previous exchanges with the DPP".