Four provinces will implement the new plan later this year, according to Zhang Feng, spokesman of the Ministry of Industry and Information Technology.

"Subscribers in South China's Hainan province will be able to freely change carriers while retain their phone numbers beginning Saturday," Zhang said.

Previous trials in the province have only allowed users to abandon China Mobile Corp's network and join services provided by smaller carriers.

Jiangxi and Hubei in Central China, as well as Yunnan in the Southeast, will roll out the new program during the third quarter, said Zhang.

It is unclear when the number portability policy will expand to other parts of the nation.

Industry regulators are gradually lifting its tight controls over commercial telecom services to spur competition.

A decades-old service fee regulation was abolished a week ago to increase sector marketability.

Lower service charges and rising competition from the country's only three carriers are expected as the government continues to ease control.