An inspection of all 91 apartment complexes with underground parking garages built using flat slabs found that 15 had weak or no structural reinforcement.

The Korea Land and Housing Corporation(LH) briefed the land and transport ministry on the findings of its probe during a meeting on public housing safety inspection chaired by land minister Won Hee-ryong in Seoul on Sunday.

The corporation said ten of the apartment blocks lacked reinforcing bars, or rebar, due to either improper structural calculations or a lack of specification in the blueprints, while five were subject to poor installation.

Of the 15 complexes, eight are in the Seoul metropolitan area and seven are in rural areas. Five already have occupants.

During Sunday’s meeting, the land minister urged LH to seek the strongest disciplinary action against those responsible for the poor design and construction management, urging the corporation to promptly launch investigations and file complaints.

The corporation’s inspection came after the absence of rebar was cited as the cause of an underground parking lot collapse in an apartment in Incheon's Geomdan New Town in April.