Impeached President Yoon Suk Yeol speaks during a hearing at his impeachment trial at the Constitutional Court in Seoul, Jan. 21. Yonhap

Acting Justice Minister Kim Seok-woo said Wednesday he considered a court's decision to release impeached President Yoon Suk Yeol from jail "unjust."

Yoon, who was detained in January on charges of inciting an insurrection through his failed bid to impose martial law on Dec. 3, was released from jail last Saturday as the court allowed the suspended president to stand trial without detention, citing some questions over investigations into his charges.

"I think the court's verdict needs to be rectified because it was unjust," Kim told lawmakers.

Yoon's release came as Prosecutor General Shim Woo-jung decided not to appeal the Seoul Central District Court's decision to grant Yoon's request to cancel his arrest, citing that his indictment came hours after the detention period had expired.

"(The prosecution) did not immediately appeal the decision because doing so would have likely contained unconstitutional elements," the acting minister said.

The court appears to have concluded that Yoon had to be released before being indicted, Kim said, vowing to challenge the issue in Yoon's main criminal trial.

Still, immediately appealing the court ruling would have been "undoubtedly" unconstitutional, Kim stated, citing the Constitutional Court's past rulings against similar cases.

"Given the previous rulings, the prosecution's judgment on whether to extend the detainment cannot precede the justice's decision," Kim said.

Chun Dae-yup, chief of the National Court Administration, an arm of the Supreme Court, also questioned the prosecution's decision to release Yoon without filing an immediate appeal.

"We believe it is necessary to receive the judgment of a higher court through an immediate appeal," he told lawmakers, noting the prosecution has seven days, until Friday, to take such action.

The Supreme Prosecutors Office responded in a notice to the press that it is "reviewing" Chun's remarks but cannot elaborate. (Yonhap)