NTT DoCoMo Inc. plans to raise its family phone discount rate to 20 percent from the current 15 percent and to reduce call rates for its mobile phone service, although the size of the cut has not yet been decided, in response to competition from other carriers, company officials said Saturday.

The operator of Internet-capable i-mode mobile phones under the Nippon Telegraph and Telephone Corp. group is planning to raise the family discount rate on April 1 and reduce the mobile phone services rate in June, the officials said.

NTT DoCoMo, however, has yet to determine by what margin to cut call rates under its plan to return profits to users with lower charges, the officials said.

Given huge consolidated pretax profits of 665 billion yen projected for fiscal 2000, which ends March 31, the cut could be more than 10 percent.

Rate-cutting competition has intensified in the mobile phone market. DDI Corp., better known as KDDI, has expanded its market share with a 50 percent student discount service that began last November.

NTT DoCoMo, which raised the family discount rate to its current level last June, hopes to attract more price-conscious housewives with the higher discount, the officials said.

The discount applies to basic usage charges and phone bills and is offered for a single contract signed for at least two and up to five family members.

NTT DoCoMo had 8.3 million family discount subscribers as of Dec. 31, accounting for 24 percent of its overall mobile phone users.