Statistics from the National Immigration Agency (NIA) suggest that while Chinese now enjoy facilitated travel to Taiwan, criminal activities perpetrated by the Chinese have also remained high, and officials are hard-pressed to keep tabs on every Chinese visitor entering the country.
More than 700 Chinese are on a list for overstaying their visa, and 211 of them may be involved in illegal activities, the agency said, adding that these were only the numbers officially recorded.
The actual numbers could be as high as 1,000 Chinese overstays, it added.
Of the 211 members not eligible for visa extension and that were suspected criminals, 60 came over on a professional visa, 38 on business, 66 on tourism and 47 medical checkups.
They disappeared shortly after entering the country, the agency said, adding that they may currently be either working at part-time jobs or may be involved in prostitution or fraud.
Some may be gathering intelligence and pose a severe national security risk, it added.
The other 573 Chinese overstaying their visas, but still within the timeframe of extending their visas, would be notified by officials, the agency said, adding that it was hard to say whether those visitors have simply forgot to extend their visas or were also involved in illegal activities.
With the variety of methods available to Chinese to enter Taiwan, the agency said human trafficking has decreased over the years.
In 1992, the government repatriated nearly 2,000 Chinese who illegally entered the country, and in 1993 the numbers climbed as high as 6,000, the agency said.
However, since 2006, the numbers have seen a decrease, with only 53 repatriated in 2011, 17 in 2012 and 21 in last year up to November last year, the agency said.
The decreasing numbers of repatriated Chinese does not necessarily reflect a decrease in illegal activities perpetrated by Chinese, but could simply mean they have more legitimate ways of entering Taiwan, the agency said.
Chinese may now enter for medical, tourism and business purposes, which is opening a lot of doors for those who want to exploit the system, the agency said.
Taiwan can only process Chinese requests to enter Taiwan based according to the information they have submitted, as accessing Chinese household registration or criminal data was difficult, it said.
It cited Ding Zhongtao (丁仲桃), a Chinese arrested for fraud in June last year, as an example.
Ding entered the country for a medical checkup, and it was not until his arrest in June that authorities realized he already had a criminal file in China, the agency said.
Officials said in private that they were concerned about the growing channels of entry available to Chinese, the shortage of manpower and lack of ancillary systems to keep tabs on their entry, adding that it had the potential to become a major problem.