Cross-straits romance is the main cause of Chinese mainland tourists staying in Taiwan illegally, the Taiwan interior department said.

Taiwan opened the door to individual tourists from the mainland cities of Beijing, Shanghai and Xiamen in 2011 and extended permission to residents of 10 more mainland cities in 2012.

By the end of November, a record 1 million individual tourists from the Chinese mainland had visited Taiwan this year, Chen Chun-ching, vice-minister of Taiwan's interior department, was quoted by the Central News Agency.