Staff at an Apple Store in downtown Shanghai clapped and congratulated iPhone 6 customers as they left the shop, which opened two hours early for those who had pre-ordered.

Fashion industry worker Wang Xue picked out a gold-coloured iPhone 6 Plus, having used an iPhone 4 for the past four years.

"I like the design and everything about it," she said. "It's worth it to me to pay USD 998."

The new gadget hits shelves in China a day after the tech giant unveiled a new line-up of iPads in United States in a bid to face off tough competition in the cooling tablet market.

Apple's products enjoy a devoted following in China, the world's second-largest economy and the largest smartphone market according to an industry estimate.

It launched the large-screen iPhone 6 and iPhone 6 Plus in 10 countries and regions on September 19, but could not do so in mainland China because it lacked a key network access licence.

Media have reported widespread smuggling of the new phone into China given its initial unavailability.

The Ministry of Industry and Information Technology granted permission late last month, but said it had pressed Apple to improve personal data security to gain approval and quoted US firm as saying it would do so.

The government agency said outside parties could obtain information stored on an iPhone by accessing a "trusted" computer or from an iPhone undergoing repair.

Apple has not responded publicly to the claims.

Customer deliveries began Friday in the company's 12 retail stores in mainland China, and through the country's three major telecom providers and other sales channels.