Apple’s iPhone launched in China last Friday with plenty of fanfare, but the sales numbers so far appear a little light. China Unicom, the iPhone’s carrier in the country, said Tuesday it has signed up 5,000 iPhone subscribers since the launch, below what some analysts were expecting.

Piper Jaffray analyst Gene Munster called the China launch a “disappointment.” He was expecting something in the range of 30,000 units. “We believe that eventually China will emerge as a major market for iPhone sales but it could take a year or two to gain meaningful unit traction as it did in the U.S.,” he wrote in a research note Tuesday.

The iPhone is Apple’s biggest growth story, with more than 30 million units sold worldwide since its launch in 2007. China represents a huge market opportunity for Apple, which is starting with about 1,000 places selling the iPhone.

In August, China Unicom signed a three-year non-exclusive deal to sell the iPhone in China, aiming to boost its launch of 3G services. However, some analysts say the handset — which costs $700 to $1,000 — will eventu