A shortage of Apple's iPhone 4, newly introduced in China, is fuelling a grey market for imported phones and anger among genuine customers plagued by scalpers, hoping to sell the phones on for profit.

According to AFP, Apple was forced to temporarily close one of its stores in Beijing after arguments broke out between scalpers and Apple store customers frustrated and disappointed at missing out on the handsets.

Scalpers have been reportedly charging an additional 300-600 Yuan ($45-90/£28-£56) to those desperate to get their hands on Apple's latest iPhone.

As Macworld previously reported, a lucrative grey market for iPhones being shipped back to China from the US, UK and elsewhere has also inflated prices.

China Unicom announced this week it had sold close to 100,000 iPhone 4s in the four days since the smartphone was launched in China last Saturday, 25 September.

Apple iPhone 4

Apple has said more iPhone 4s will be made available in China soon and that customers should check back with their local store for updates. China Unicom expects the second shipment of the iPhone 4 to arrive in China today,  1 October, during the country's National Day Holiday.

Apple has priced its iPhone 4 without a contract at 4,999 Yuan ($744/£468) for the 16GB model and 5,999 Yuan ($893/£562) for the 32GB model. China Unicom offers the iPhone 4 with a new two-year contract.

AFP adds China has at least 420 million web users and is the world's largest mobile market with more than 800 million subscribers as of the end of June 2010, according to official data.