Apple Inc's next-generation iPhone has not even been released yet, but opportunistic sellers on China's largest e-commerce platform, Taobao, are already accepting pre-orders, complete with mock-up pictures and purported technical specifications.

The hotly anticipated iPhone 5 is widely expected to be released sometime between August and October this year, although Apple itself has been tight-lipped about it. Sources have said the iPhone 5 would have a bigger screen than previous models, while Taiwanese media reported the phone's voice recognition software, Siri, would have more powerful functions.

Sellers on Taobao, a unit of Alibaba Group, are accepting orders for the iPhone 5, in some cases asking for a deposit of 1,000 yuan ($160) for the new phone. One seller, "Dahai99888", who started accepting pre-orders this week, is asking for full payment upfront, at a cool 6,999 yuan ($1,100).

Taobao sellers that Reuters spoke with said they planned to buy the iPhone 5 in Hong Kong or the United States and then bring it to mainland China. Apple products are often available in Hong Kong before they are released on the mainland.

The sellers could not promise a specific delivery time.

The pre-order activity comes despite the mystery around the iPhone 5 and highlights the intense demand for new Apple products in China.

Apple has not confirmed the specifications, details or price of the latest iPhone, but the Internet rumor mill has been in overdrive, churning out photo renderings and pictures of purported iPhone 5 engineering samples and speculating endlessly on its technical specifications and functions.

Apple did not respond to requests for comment.

"Demand is high. Yesterday someone just bought two phones. Altogether we have about two dozen orders," said one seller on Taobao who went by the nickname Xiaoyu.

On Alibaba.com, the business-to-consumer platform of Alibaba Group, hard-shell cases and soft silicone cases for the iPhone 5 were peddled by sellers, most located in southern China. The majority of cases indicate an elongated iPhone 5 with some showing an earphone jack located at the bottom. One verified Alibaba.com seller Reuters spoke to "guaranteed" the cases were accurate, saying the company's boss received the dimensions from "certain channels".

Although it is hard to know whether the cases on Alibaba.com reflect the real deal, the sellers have been right before. In early 2011, cases for the yet-to-be-launch iPad 2 appeared on Alibaba.com, showing accurately the placement for a rear-facing camera.

Demand for Apple products in China is so high that many consumers buy smuggled goods in order get them before the official China release. Earlier this year scalpers queued overnight outside a Beijing store for the latest version of the iPhone 4, only to pelt the store with eggs after Apple decided against selling the phone there because of security concerns.

"It's not so easy to bring the phones from overseas, there's a limit to how many you can carry in...If we could bring in a few thousand that will be great!," said Xiaoyu.

One enterprising seller posted a list of 17 possible new iPhone 5 features and gave a percentage probability that they would be included in the new device. For example, a biometric capability has a 20 percent chance of being a feature on the iPhone 5, according to the seller.

Apple, which recently settled an iPad trademark lawsuit with a Shenzhen technology firm, said on Tuesday it would release its latest iPad in China on July 20.

Apple has five stores in mainland China and plans to open flagship stores in the major Chinese cities of Chengdu and Shenzhen, according to government officials.

($1 = 6.3686 Chinese yuan)