Apple Inc's latest iPhone 4S will likely be sold in the Chinese mainland by the end of this month, a senior official of China Unicom, Apple's domestic carrier partner for the smartphone, said during the weekend.

Apple is expected to get approval this week from the Chinese regulator to sell the iPhone 4S in the domestic market, which is the world's biggest mobile phone market with more than 900 million users, according to the telco. The iPhone 4S is already sold in many regions including the United States and Hong Kong.

The two partners will probably launch the iPhone 4S by the end of December, according to Yu Yingtao, China Unicom's sales department general manager.

"China Unicom is fully prepared for the launch of the iPhone 4S," Yu said during a TV interview at the weekend.

Apple China, however, yesterday declined to comment on the issue.

Apple sees a huge potential for its products in China, now the second largest market for the firm. In the third quarter, Apple's China revenue surged six-folds annually to US$3.8 billion while iPhone sales tripled in the quarter from a year ago.

China Unicom will sell the iPhone 4S with two-year contract.

In October, Apple sold over 1 million iPhone 4S models in the US within 24 hours after its debut. The global sales of iPhone 4S will surpass 25 million units in the fourth quarter, a 77 percent surge from iPhone 4 sales in the same quarter a year ago, according to Piper Jaffray, a US-based investment bank.