The government will not ask telephone companies to voluntarily participate in police wiretapping operations, Justice Minister Okiharu Yasuoka said Tuesday, the day that Japan's first-ever wiretapping law took effect.

"We will not ask these companies to develop equipment or send employees" to monitor police wiretapping without remuneration, he said, adding that authorities may instead rely on civil servants in municipal governments to serve as monitors.

Yasuoka's comments came after Japan's largest cellular phone company, NTT DoCoMo Inc., said it will refrain from sending staff to monitor operations due to concerns over cost and stress to its employees.