Prime Minister Kim Boo-kyum has said the "undisputed power" of the prosecution needs to be held in check, referring to President Moon Jae-in's green light on Tuesday on two controversial bills designed to eventually strip the prosecution of its investigative powers.

Kim told reporters on Tuesday that unfettered authority must be restrained, citing a case in which the prosecutors conducted their own investigation into bribery allegations against fellow prosecutors that ultimately ended without charges.

In response to fears over the transfer of investigative rights to the police, the prime minister said that they will not have a monopoly on investigative authority as there are checks and balances within the system, and emphasized that the prosecution's supplementary investigative rights are also powerful.

He added that if the reforms prove to benefit criminals over the general public, they will need to be remedied.