The landslide occurred at around 6 p.m. Friday after residents earlier noticed water flowing onto the road. Department of Public Works and Highways personnel also observed water coming from the upper portion of the mountain during an inspection.
The Mabini Municipal Disaster Risk Reduction and Management Office said saturated soil following successive rains is being considered as a possible cause of the slope failure.
Two families were evacuated from the area because of the threat of another landslide.
Four utility poles of Batangas II Electric Cooperative were also affected, resulting in power interruption in Barangays San Teodoro and Mainit.
DPWH Batangas 2nd District Engineering Office OIC District Engineer Ariel Armedilla said authorities had ordered the affected portion of the circumferential road closed before the slope completely gave way.
The affected road section remained closed as of the latest available report Sunday, with motorists advised to avoid the area while authorities continue monitoring conditions.