By Neil Hughes

Published: 02:10 PM EST (11:10 AM PST)

The iPhone 4 has been selling at a pace much faster than its predecessor, the iPhone 3GS, serving as evidence that China is catching "Apple fever," according to one analyst.

Brian White with Ticonderoga Securities issued a note to investors Monday in which noted yet again that the iPhone 4 continues to be scarcely available in China. Apple has struggled to meet demand for its smartphone since it first launched in September.

"We continue to believe that China remains in the early stages of catching 'Apple fever' and demand for iPhone 4 has been well above the ramp of the iPhone 3GS thus far," he said.

White recently toured China and met with officials from the nation's wireless carriers. They indicated they believe the total high-end smartphone market in China is between 100 million and 125 million.

That huge addressable market could prove to be a "significant opportunity for growth" for Apple in the years ahead, White said.

"The iPhone 4 is sold out for two months at authorized Apple resellers, Apple stores and China Unicom," he said. "In fact, we estimate China Unicom has been unable to fulfill approximately one-third of the iPhone 4 orders due to shortages.

The iPhone 4 got off to a hot start on carrier China Unicom in September, when it sold 100,000 in its first four days. Since then, limited supply led to extensive scalping, forcing Apple to require reservations for purchases.

And China Mobile, which is not an official partner with Apple, has been helping users trim their SIM card to fit inside the iPhone 4, which requires a microSIM. White noted that even though China Mobile does not sell the iPhone 4, it has the most iPhone subscribers on its network.