NTT DoCoMo Inc, Japan's biggest mobile phone carrier, said it may restructure its regional sales units, as it battles a price war against aggressive rivals seeking to grab market share.

A merger of the eight regional units, which employ about 6,000 staff, is under consideration, DoCoMo spokesman Roland Arafat said on Tuesday. He declined to comment on how much such a move would save.

DoCoMo, which has also been squeezing handset costs to free up cash for marketing, lost a net 22,900 users to rivals KDDI Corp and Softbank Corp in August. [nT263436]

Softbank, the smallest of Japan's three mobile phone operators, won more new users than either DoCoMo or KDDI for the fourth straight month last month, thanks to low-cost mobile plans it adopted after buying Vodafone's Japan unit last year.

DoCoMo and KDDI, which together control more than 80 percent of Japan's cellphone market, are halving their basic fees this month to match Softbank's prices in the saturated market.

Shares of DoCoMo, which have shed more than a quarter from their peak for the year in February, fell 2.4 percent on Tuesday, while KDDI fell 1.3 percent and Softbank rose 0.7 percent.