TOKYO, April 15 (Xinhua) -- Japan's telecom operator NTT Docomo Inc. said on Monday that it would reduce its mobile phone fees by up to 40 percent starting in June as the Japanese government called for lower telecom service charges.

"We will introduce simpler and more reasonable service fee plans after receiving many voices that they have been complicated and difficult to understand," Kazuhiro Yoshizawa, president of NTT Docomo, told a press conference in Tokyo.

Yoshizawa said the plan of new service charges would reduce the company's income by as much as 400 billion yen (3.57 billion U.S. dollars) per year.

"I recognized some moves (within the government) but we decided to launch the new fee plans to become the leader in the mobile phone market," the president said.

The company said it would provide two basic sets of service charges, one for a monthly fee of 5,980 yen (53 dollars) with unlimited data and another for 1,980 yen (18 dollars) with less volume of data.

NTT Docomo also plans to introduce separate charges for handsets and services in order to simplify the plans of fees, as major Japanese wireless carriers are often criticized for the complexity of their charge plans which make it difficult for consumers to compare fees with other companies.

Japan's Chief Cabinet Secretary Yoshihide Suga had called on mobile phone service operators to lower fees, as Japanese operators generally charge higher than those in other countries and major cellphone companies tend to earn higher profit margins than other industries.

In April 2018, the Japanese government approved e-commerce giant Rakuten Inc. to operate mobile services starting from October this year, which is expected to evoke greater competition.