Apple's Wi-Fi-enabled iPhone will debut in the domestic market on Monday, a source from Apple's Chinese partner China Unicom revealed Thursday.

At present, all iPhones sold in China come without Wi-Fi, which provides the smartphones with high-speed Internet access and allows for better experience, according to experts.

The new Wi-Fi-enabled iPhone 3GS with 8GB (gigabyte) storage space will cost 4,999 yuan (US$735), 20 percent cheaper compared with former entry-level 16GB model iPhone 3GS, according to the China Unicom source, who declined to be identified.

On Apple China's website, the tech standard introduction claims that the new iPhone 3GS 8GB will "soon be available" in the country, with Wi-Fi function.

Apple debuted the iPhone in the world's biggest mobile market in 2009, through its cooperation with partner China Unicom, the country's No. 2 mobile carrier.

The high price (starting from 5,880 yuan) and the lack of Wi-Fi function adversely affected the sales of iPhone in China, insiders said.

Instead, many users chose to purchase Shuihuo, or smuggled, iPhones in the gray market, which feature Wi-Fi functions.

Thanks to Wi-Fi, users enjoy a better experience on the iPhone with strong Internet functions via a big touch-screen and Safari Internet browser.

In the first half of this year, more than 400,000 iPhone units were sold in the gray market, compared to 500,000 sold with China Unicom, research firm BDA said.