The communications ministry plans to prohibit global information technology giants from using email content and other communications data without users’ consent, informed sources said Friday.

Domestic companies are already subject to the restriction, as Japan’s telecommunications business law requires them to observe a constitutional guarantee of the secrecy of communications.

Among them, however, are mounting complaints that their overseas rivals, including Google Inc., Apple Inc., Facebook Inc. and Amazon.com Inc., freely use their data for marketing, bringing in large profits.

The ministry is slated to consider specific ways to enforce Japanese law on global technology companies.

Late last year, the government drew up a basic policy to regulate major global technology firms. The Fair Trade Commission plans to conduct an investigation into them for possible action under Article 40 of the antimonopoly law.