TOKYO -- Japan's Immigration Services Agency is to tighten the screening process for issuing student visas, increasing tenfold the number of countries subject to stricter checks starting with foreign nationals applying from April.

Under the measure, which is aimed at preventing foreign nationals from using student visas as a way to gain entry to Japan and work illegally in the country, the agency says it will ask applicants from the expanded list of countries to submit documentation including diplomas and account balance certificates.

After a growing number of foreign nationals have entered Japan and stayed beyond their visa expiration dates, the government has decided to tighten screening procedures to ensure sound growth of foreign nationals working in Japan. The measure is also aimed at promoting use of the country's "specified-skills" work visa program that was introduced in April 2019 but has been underused.

The latest move represents the first major overhaul of Japan's student visa screening system in about three decades.

Currently, students from seven countries -- China, excluding Hong Kong and some other regions, Vietnam, Nepal, Sri Lanka, Myanmar, Bangladesh and Mongolia -- are subject to enhanced student visa screening processes. As many nationals of those countries have been found to overstay illegally, Japan requires them to submit multiple documents, including the applicant's highest academic level of diploma, the account balance certificate of a relative who plans to pay for the applicant's living expenses in Japan, and an official document proving the applicant's relationship with the relative.

However, there have been many cases in which foreign students outside this scope have stayed in Japan after graduating from local schools. At the beginning of 2019, foreign nationals who had been allowed to enter Japan for study purposes but overstayed illegally totaled about 4,700, increasing 70% from 2,800 in 2015.

The figure makes student visa overstayers second only to the 47,000 short-term residents who overstay, including many who entered Japan without undergoing screening, and about 9,000 technical trainees, many of whom have gone missing in the country.

Vietnamese nationals account for the highest share of student visa overstayers, totaling 3,065, followed by Chinese and South Koreans, accounting for 1,074 and 148, respectively.

China is now included in the whitelist as the number of overstaying Chinese students has decreased as the country's wealthy population bracket has grown. Eighty countries, including India and Cambodia, which have been approved by the Japanese government, are not included in the whitelist.

Foreign students are allowed to work in unskilled-labor positions, such as convenience store work, for up to 28 hours per week. According to the Japanese Ministry of Health, Labour and Welfare, students accounted for 19%, or 318,000, of foreign workers in Japan in October 2019. The majority of foreign students are believed to take jobs during their stay.

According to a 2018 survey by the Japan Student Services Organization, foreign students in Japan included about 6,200 from Indonesia, 2,300 from the Philippines, and 2,100 from Uzbekistan, all of which are not included in the whitelist.

As the introduction of the stricter screening process may result in fewer foreign students going to Japan, it may affect retailers and restaurant operators that heavily rely on their labor.

Convenience stores in Japan heavily rely on foreign student part-time workers.

The Immigration Services Agency has included 118 countries of origin for student visa applicants in a "whitelist" in view of their relatively stable economic situations and low risk of individuals from those places overstaying. Starting in April, individuals from any country or region not on the whitelist applying for student visas will be subject to a screening process as strict as that applied to those from the seven countries, including the requirement to submit multiple certificates.

"We are going to be stricter on students from countries many of whose nationals have overstayed," a government official said. "Our hope is that businesses will hire [foreign students] appropriately, taking advantage of the specified skills program."

"Retailers and restaurant operators must wean themselves off their reliance on foreign student part-timers and work to shorten open hours and improve productivity," attorney Koji Yamawaki, who is knowledgeable about labor management of foreign nationals, said.

"They should shift to other foreign workers qualified to perform unskilled work, such as those that have the specified-skills visa status, although recruiting them presents a higher hurdle," Yamawaki said.

The 80 countries subject to the immigration agency's tougher screening process for foreign students are:

Afghanistan, Angola, Bangladesh, Bhutan, Burkina Faso, Burundi, Benin, Bolivia, Cape Verde, Cameroon, Cambodia, Central African Republic, Chad, Cook Islands, Comoro, Republic of Congo, Democratic Republic of Congo, Djibouti, East Timor, Egypt, Eswatini, Ethiopia, Eritrea, El Salvador, Ghana, Gambia, Guinea, Guinea Bissau, Haiti, Honduras, India, Indonesia, Ivory Coast, Kiribati, Kyrgyzstan, Kenya, Laos, Lesotho, Liberia, Madagascar, Malawi, Mali, Federated States of Micronesia, Myanmar, Mauritania, Mozambique, Moldova, Morocco, Mongolia, Nauru, Niue, Nicaragua, Niger, Nepal, Pakistan, Papua New Guinea, Philippines, Rwanda, Sao Tome and Principe, Senegal, Sierra Leone, Somalia, Solomon Islands, South Sudan, Sudan, Sri Lanka, Syria, Uganda, Ukraine, Uzbekistan, Tajikistan, Tanzania, Tunisia, Togo, Vatican, Vanuatu, Vietnam, Yemen, Zambia and Zimbabwe,.