South Korea's health ministry said Tuesday that it has decided to ask the prosecution to investigate the head of a globally renowned medical group on suspicions of using donated cord blood without authorization.

The ministry said it was also revoking its designation of Cha Medical Group as a state cell bank, a move that will force the medical group to return some 500 million won ($414,660) it has received in government support.

Cord blood is blood that remains in the umbilical cord after childbirth, and is full of stem cells that can be used to treat genetic disorders.

The ministry earlier said Cha Kwang-yul, head of Cha Medical Group, and his wife, as well as Cha's father, are believed to have received unauthorized medical treatment using donated cord blood on nine separate occasions.

Ministry officials said the prosecution investigation will verify whether Cha had personally instructed or demanded the unauthorized use of the donated blood on himself and his family.

They said the ministry will also recover 518 million won it has provided to Cha Medical Group since its designation as a national cell bank in 2015, adding the ministry plans to reject any future requests from the group for its use or supply of cord blood, a move that may effectively force the group to at least shut down its stem cell business.

Cha group came under public scrutiny following allegations that it had provided unauthorized, if not illegal, medical services to President Park Geun-hye and her close friend Choi Soon-sil, who is currently facing a criminal trial over a corruption scandal that has also led to the impeachment of Park. (Yonhap)