NTT DoCoMo Inc. is negotiating to buy into Philippine Long Distance Telephone Co., the largest telecommunications firm in the Philippines, company officials said Wednesday.

Philippine President Gloria Macapagal Arroyo announced the planned investment earlier in Manila, saying the leading Japanese mobile phone service provider will inject some $300 million into PLDT.

The investment by DoCoMo would give it a stake of some 5 percent in the firm, which also owns the Philippines' biggest mobile phone service provider, Smart Communications Inc.

PLDT obtained a license to provide third-generation mobile communication services in late 2005 and 3G service is scheduled to begin sometime this year. The company will adopt the WCDMA communication standard used by DoCoMo.

Industry analysts said DoCoMo is expected to provide its i-mode mobile Internet technology to PLDT. The two firms are also likely to cooperate in procuring handsets and expand roaming services so the handsets can be used in both countries, they said.

In 2000, NTT Communications Corp. bought a 15 percent stake in PLDT. DoCoMo may buy part of the NTT Communications share, according to sources close to the deal.

DoCoMo is stepping up investment in Asia. In December, it agreed with South Korea's number-two mobile service provider, KT Freetel Co., to invest about 65.5 billion yen to acquire a 10 percent stake in the firm.