UPDATE 1-Japan Communications Net cellphone to enter price war

(Adds company comments, share price, earnings forecast)

TOKYO, April 21 (Reuters) - Japanese wireless data communications provider Japan Communications Inc (9424.OJ: Quote, Profile, Research) said on Monday it plans to launch Internet mobile phones in a move that could exacerbate price competition in a saturated market.

The provider, which uses NTT DoCoMo Inc's (9437.T: Quote, Profile, Research) network, said the new service would help it post a 594 million yen ($5.72 million) net profit in the year to March 2009, swinging from an expected 1.95 billion yen loss in the business year just ended.

Japan Communications officials said it is considering charging a fixed monthly rate for its mobile phone service, which could launch as early as July and include free calls via Internet networks.

The move marks a new twist in Japan's mobile phone market of 107 million subscribers, where DoCoMo and rivals KDDI Corp (9433.T: Quote, Profile, Research) and Softbank Corp (9984.T: Quote, Profile, Research) have been slashing prices in a fierce battle for market share.

"The next step will be to expand services overseas," said Japan Communications CEO Frank Sanda, who was unfazed by glitches that halted a demonstration of the new Internet phones.

"Japan is the world's most advanced mobile market and the leader in mobile infrastructure, yet its handset makers hold little global market share and mobile charges remain high. That's not right."

The venture's shares closed up 9.8 percent at 44,700 yen, compared with Tokyo's broad Topix index , which rose 2.1 percent. (Reporting by Mayumi Negishi; Editing by Quentin Bryar)