Apple has begun keeping the personal data of some Chinese users on servers in mainland China, marking the first time the tech giant is storing user data on Chinese soil.

The storage of user data in China represents a departure from the policies of some technology companies, notably Google, which has long refused to build data centres in China due to censorship and privacy concerns.

Apple said the move was part of an effort to improve the speed and reliability of its iCloud service, which lets users store pictures, e-mail and other data. Positioning data centres as close to customers as possible means faster service.

The data will be kept on servers provided by China Telecom, the country's third-largest wireless carrier, Apple said in a statement on Friday. "Apple takes user security and privacy very seriously," it said. "We have added China Telecom to our list of data centre providers to increase bandwidth and improve performance for our customers in mainland china. All data stored with our providers is encrypted. China Telecom does not have access to the content."

A source with knowledge of the situation said the encryption keys for Apple’s data on China Telecom servers would be stored offshore and not made available to China Telecom. Apple has said it has devised encryption systems for services such as iMessage that even Apple itself cannot unlock.

But some experts expressed scepticism that Apple would be able to withhold user data in the event of a government request. "If they're making out that the data is protected and secure that's a little disingenuous because if they want to operate a business here, that'd have to comply with demands from the authorities," said Jeremy Goldkorn, director of Danwei. com, a research firm focused on Chinese media, internet and consumers.

"On the other hand if they don't store Chinese user data on a Chinese server they're basically risking a crackdown from the authorities." Goldkorn added that data stored in the United States is subject to similar US regulations where the government can use court orders to demand private data. A spokesman for China Telecom declined to comment.

Reuters