The policy of the Chinese mainland toward Taiwan will remain unchanged in 2017 despite a possible increase in uncertain factors and challenges in cross-Straits relations, the mainland's Taiwan affairs chief said on Sunday.

Zhang Zhijun, head of the Taiwan Affairs Office of the State Council, told reporters before the opening of the annual session of the National People's Congress that cross-Straits relations faced more complicated and severe challenges this year.

"However, our policies toward Taiwan will not change because of the change in the political situation in Taiwan," he said.

Zhang said the Chinese mainland will resolutely uphold the one-China principle and oppose "Taiwan independence", and safeguard the peace and stability in cross-Straits ties.

The Chinese mainland will also promote cross-Straits exchanges and more coordinated social and economic development across the Straits.

Since the Democratic Progressive Party took over leadership in Taiwan in May 2016, cross-Straits relations have worsened and official communication has been suspended.