(Yicai Global) Oct. 27 -- China's Ministry of Industry and Information Technology (MIIT) has called in the nation's big three telecom operators and ordered them not to restrict users' right to choose among different tariffs and to take immediate corrective measures to address the problem of existing users being unable to switch to new packages.

MIIT hopes that the three carriers strictly abide by relevant government documents and do not restrict existing users' right to choose, said Wen Ku, head of the ministry's telecom development department.

The ministry is also urging the companies to check their existing plans and take immediate corrective measures if any restrictions pop up, he added.

Users of some carriers are unable to subscribe to packages they offer in tandem with third-party internet firms, with the carriers saying this results from system upgrades. MIIT has instructed these companies to help users change packages manually.

Customers of China United Network Communications Group Co., one of the nation's big three carriers, are unable to change packages online by themselves since the internet-focused packages are still in the pilot phase and have substantially different fee-charging rules from existing packages, the firm said earlier, adding that it is optimizing and upgrading its system.

The other two leading carriers are China Telecommunications Corp. and China Mobile Communications Corp.