The revised mining law took effect Saturday, tightening control of the exploration and development of seabed mineral resources.
Japan has already discovered underwater resources such as natural gas and rare metals in its surrounding waters, but there were no regulations previously concerning their exploitation.
The first major revision to the mining law, enacted in 1950, requires companies to obtain advance approval from the trade minister to mine such resources. The measure is intended to prevent the unregulated exploitation of seabed resources.
Under the revised law, the trade minister must confirm that firms have the requisite technological capabilities and financial resources for test drilling and underwater mining. In the past, some companies were granted approval despite their limited mining experience and failed to fully develop sites on the seabed.