Lee's move to launch a new probe came as he met the bereaved families of victims from recent major disasters, including the Halloween crush in Seoul's Itaewon district, his spokesperson Kang Yu-jung told a briefing.
Lee, who took office in June, has promised to make the country safer and to prevent any repeat of the disasters in recent years that have often been blamed on the inadequate response by authorities.
The president said the new investigation team would work alongside aspecial commission that was launched in September last year to look into the case, according to the spokesperson.
At the meeting with Lee, Song Hae-jin, a representative for the families of the crush victims, said police records and information regarding the government's response to the disaster had been withheld from the special commission.
During his meeting with the bereaved families, Lee bowed deeply as he apologised for any failures by authorities.
"As the head of the state, I would like to formally apologise on behalf of the government for failing to fulfill its responsibility to protect the lives and safety of the people, and for the many people who lost their lives as a result," he said as some relatives wept.
(Reporting by Ju-min Park and Jack Kim; Editing by Ed Davies)

South Korean President Lee Jae Myung places a bouquet of flower at an underground roadway in the town of Osong, Cheongju, central South Korea, 14 July 2025, to pay tribute to the 14 people who were killed in the flood-hit tunnel following the overflowing of a nearby river triggered by torrential rain on 15 July 2023. EPA/YONHAP / POOL SOUTH KOREA OUT