South Korea's spy agency has decided not to send a group of 13 North Korean restaurant workers to a state-run resettlement facility as it plans to hold them under its protection, government officials said Tuesday.

The National Intelligence Service has notified Seoul's unification ministry that it will put the group of 13 North Koreans who defected to Seoul en masse in April under its protection for their safety.

"The NIS has notified the government that its decision was made for their security, given that the case is a high-profile defection and North Korea is using it as propaganda," said a ministry official.

A group of 12 female staff and one male manager fled a North Korea-run restaurant in China's eastern port city of Ningbo and defected to South Korea in early April.

Usually, North Korean defectors receive a three-month resettlement education at the facility named Hanawon after coming to South Korea. The government offers five-year protection to them.

The spy agency's decision comes as a local court plans to open a hearing later in the day to decide whether it is legally proper for the government to hold the North Korean defectors.

An association of progressive lawyers requested the court to decide on the legality of Seoul's protection of the defectors in a bid to investigate North Korea's claim that they were kidnapped by Seoul.

The government said that they came to South Korea on their own free will, but the North claims that they were "lured and abducted" by the South Korean government, calling for their immediate repatriation.

The legal proceedings kicked off as the NIS earlier rejected the request by the Lawyers for a Democratic Society, or Minbyun, to meet with the restaurant workers to clarify the North's claims. (Yonhap)