The government will launch a special inspection into domestic budget airlines next week over their safety practices and impose heavy sanctions on violators of related rules, the transportation ministry said Friday.

Low-cost carriers (LCCs) have been under fire for two recent problems, which have sparked concerns over their safety.

An airplane of Jeju Air Co., owned by mid-sized retailer Aekyung Group, dived to an altitude of 8,000 feet from 18,000 ft on its way to Jeju Island from Seoul on Dec. 23 with about 150 passengers aboard due to a defect in its air pressure regulator.

On Sunday, a plane of Jin Air Co., a low budget airline unit of No. 1 Korean Air Lines Co., carrying some 160 passengers to Busan, was forced to make an emergency return to an airport in the Philippines shortly after takeoff as one of its doors was found to be improperly closed.

No injuries were reported from both cases, but passengers complained of headaches and nausea.

The Ministry of Land, Infrastructure and Transportation said that it will carry out a special scrutiny over safety of local budget carriers next week.

"The special inspection will start next week," said Vice Minister Choi Jeong-ho in a meeting with high-ranking officials and safety managers of the companies. "If there are any problems related to safety, we will close air routes and suspend operations."

He said the government will take all measures to apply sanctions against accidents that threaten safety and people's lives.

There are six LCCs operating in South Korea, including Jeju Air, Jin Air, Air Busan Co., affiliated with Asiana Airlines Inc., and Tway Air Co.

The South Korean LCCs took up more than 50 percent of domestic air passengers for the first time last year. They began their commercial operations in 2005.

But they reported 50 safety accidents or defects last year, up from 32 cases in 2014. (Yonhap)