China will adopt a controversial law that mandates strict data surveillance and storage for firms working in the country from this week.
The Chinese government said the legislation was in response to increased threats from cyber terrorism and hacking.
The law, passed in November by the country's largely rubber-stamp parliament, bans online service providers from collecting and selling users' personal information, and gives users the right to have their information deleted in cases of abuse.
"Those who violate the provisions and infringe on personal information will face hefty fines," the official Xinhua news agency said without elaborating.
Overseas business groups have been pushing Chinese regulators to delay implementation of the law, saying the rules would severely hurt activities.
Until now, China's data industry has had no overarching data protection framework, being governed instead by loosely defined laws.
However, overseas critics say the new law threatens to shut foreign technology companies out of sectors the country deems "critical", and includes contentious requirements for security reviews and data stored on servers in China.