The "three illegals" as they are known - the illegal entry, residence and employment of foreigners - have developed into a serious problem.

According to the government, the number of people entering China has increased by 10 percent a year since 2000, with the number of illegal foreigners also increasing rapidly. A growing number of foreigners entering, living or working in China illegally have resulted in challenges to social management. More than 20,000 illegal foreigners were dealt with nationwide in 2011.

China promulgated the Law on Control of the Entry and Exit of Aliens in 1985, which stipulates that foreigners must obtain the permission of the authorities in order to enter, transit or reside in China. The Rules for the Administration of Employment of Foreigners in China promulgated in 1996 stipulates that foreigners may work within Chinese territory only after they obtain an employment permit and a temporary residence certificate.

Violations of the immigration and employment laws should not be excused just because of their long-term existence, so the authorities' crackdown is justified. Beijing has begun a 100-day crackdown on foreigners residing and working illegally in the capital, and some other Chinese cities have followed suit.

In order to maintain their livelihoods, foreigners who lack a legal entry visa, a legal residence permit or a legal work permit in China have to take part in illegal employment or else engage in criminal activities.

Actively implementing the relevant laws and regulations reflects the progress of society and the enhancement of China's legal system. The crackdown on illegal aliens not only protects the rights and interests of Chinese citizens, it also protects the rights and interests of foreigners who are living and working in the country legitimately.

Curbing the illegal entry, residence and employment of foreign nationals can help create a more harmonious and more equitable social environment. In fact, penalties against illegal foreigners are not that severe in China. Public security organs at or above the county level may give illegal aliens a warning, a fine, detention, an order to leave the country by a certain date or expulsion. If the circumstances of the case are serious enough to constitute a crime, criminal responsibility is investigated in accordance with the laws.

Foreigners working illegally in China can be fined between 5,000 yuan ($792) and 20,000 yuan, and may be detained 5-15 days for serious violations. Those who illegally provide job placement services for foreigners or illegally employ foreigners can be fined between 5,000 yuan and 50,000 yuan.

According to the newly revised Criminal Procedural Law, the Primary People's Courts have jurisdiction as courts of first instance over criminal cases in which the offenders are foreigners.

Besides upgrading the law, attention should be paid to its implementation, in particular, the problem of illegal employment. For example, some foreign language training institutions employ foreigners who hold no employment visa as teachers. Whether they have the skills and experience required for the work is questionable.

Foreigners without a legal identity are willing to work for longer hours for less pay. However, although hiring illegal foreigners might save costs, it also has hidden risks. Without an employment visa, both the foreign employees and the employers will suffer from possible unilateral violation of their labor contract, which has no legal validity.

In 2011, the Ministry of Human Resources and Social Security issued the Interim Measures for the Participation in Social Insurance of Foreigners Employed in China, which includes legitimate foreigners in the countries' social insurance system.

With more and more foreigners coming to China looking for work, relying on a crackdown to deal with the problem of illegal aliens is not enough. A draft law on China's exit and entry administration is currently being deliberated by China's legislature to address the problem. If the entry conditions can be relaxed, procedures simplified and efforts made to promote illegal aliens gaining legal status, it will reduce the problems caused by the illegal entry, living and employment of foreigners.

The authors are Shanghai-based lawyers specializing in labor disputes.