PHNOM PENH, Jan. 22 (Xinhua) -- More than 30,000 foreigners had applied for work permits at Cambodia's Labor Ministry in 2015 after the General Department of Immigration (GDI) had constantly inspected foreign laborers in the country, a GDI's senior official said Friday.

Speaking at the GDI's annual meeting, GDI's deputy director general Lt. Gen. Keo Vanthon said the fee for a work permit is 100 U.S. dollars a year.

He added that last year, the GDI fined 1,930 foreigners for working without employment cards, earning 241,250 U.S. dollars.

According to the GDI's report, last year, the Southeast Asian country deported 4,424 undocumented foreigners to their birth countries, 90 percent of them are Vietnamese nationals.

Under the kingdom's immigration law, any alien living in the country without valid documents such as passports, visas, or work permits are subject to deportation.