Telecommunications minister Toranosuke Katayama said Friday his ministry will maintain a policy of ensuring that the interconnection fees Nippon Telegraph and Telephone Corp. charges other carriers for access to its lines will remain competitive.

Katayama made the statement a day after five rival carriers to NTT took legal action to nullify the ministry's approval of a hike in connection fees they pay NTT. He also suggested that their lawsuit is not the Japanese way of doing things.

"Promoting fair competition is a fundamental policy of mine that cannot be shaken," the minister said at a news conference.

KDDI Corp., Japan Telecom Co., Poweredcom Inc., Cable & Wireless IDC Inc. and Fusion Communications Corp. each filed a lawsuit against the ministry to force it to reverse its April 22 approval of a request by NTT East Corp. and NTT West Corp. for an average 5 percent raise in the fees they charge other carriers to access their phone lines.

It was the first time that a telecom operator has sued its regulator.

In the lawsuits, the five carriers claim that the ministry's rate hike approval is inconsistent with its stated competition policy.

The ministry said it has tried to encourage competition through gradual reductions in NTT's interconnection fees, but it has sided with NTT by approving its latest rate hike request, according to the five carriers.

Katayama said he told the presidents of the five carriers Wednesday that they should not have taken legal action over the case.

"Resorting to legal action (over this kind of case) has been popular in the United States," he said. "But such efforts are not harmonious with Japan's (legal) culture."