The Financial Services Commission last month filed a complaint against the biotech arm of conglomerate Samsung Group, saying it intentionally breached accounting rules ahead of its 2016 listing.

Samsung BioLogics denied wrongdoing and filed an administrative lawsuit against the regulator.

Prosecutors on Thursday also raided Samsung Biologics' auditing firms Samjong KPMG and Deloitte Anjin, Yonhap News Agency reported.

An official at the Supreme Prosecutors' Office in Seoul declined to comment when contacted by Reuters. A spokesman at Samjong KPMG did not have immediate comment, and a spokesman at Deloitte Anjin declined to comment.

South Korea's main stock exchange on Monday said Samsung BioLogics was qualified to continue being listed on the bourse. Trading of the firm's shares resumed on Tuesday, having been suspended since the regulator detailed its findings on Nov. 14.

(Reporting by Heekyong Yang; Additional reporting by Hyunjoo Jin; Editing by Christopher Cushing)