Japan's NTT DoCoMo is being hailed as the ideal partner for Hutchison Telephone, Hutchison Whampoa's joint venture with United States-based Motorola.
The cellular operator is often described by analysts as being high in subscriber numbers but low in earnings and quality.
NTT DoCoMo, which has agreed to pay $3.18 billion for a 19 per cent stake in Hutchison Telephone, plans to introduce technology to make the company with Hong Kong's largest base of mobile-telephone subscribers more competitive.
NTT DoCoMo, which is the world's largest mobile-phone operator, has the most advanced network of third-generation technology that will bring applications such as Internet, e-mail and video-conferencing to handsets.
Hutchison Telephone may boast it has 1.3 million mobile subscribers, but analysts point out many of them were attracted by heavily subsidised tariffs and through free handset offers.
The company badly needed the technical expertise a partner such as NTT DoCoMo could give in order to upgrade services in preparation for the eventual launch of third-generation services in Hong Kong, analysts said.