Apple has confirmed that iPhone 4S handsets in China are suffering from issues associated with the use of a China Mobile SIM card, with both the Cupertino-based company and mobile confirming the card is incompatible with the device.

Jinghua.cn reports that China Mobile subscribers have been unable to activate the iPhone 4S, with some suffering from a complete loss of signal and others unable to receive calls despite having a full signal.

According to the Chinese publication, Apple’s customer service staff have identified the issue and have said the company is working to release a fix for the iPhone 4S. It is not known whether the company will make the update available to just the Chinese market or roll out the fix when the company makes its next iOS firmware update available to all.

An unofficial fix has been offered, which includes amending the iPhone’s network settings on the device and upgrading to Apple’s 9A406 iOS update, but it is not known if it can remedy the issue for all China Mobile iPhone handsets.

It’s interesting to see Apple and China Mobile commit to the issue, especially after China Mobile identified late last year that its SIM cards were compatible with the new iPhone. Today’s report suggests that whilst there may be some issues with a batch of China Mobile SIM cards, Apple also says that it is down to the iPhone’s unstable phone system.

All of that besides, China Mobile is the world’s biggest mobile operator, which might explain why Apple has moved to confirm issues and alerted customers that a fix on its way.

The iPhone 4S is “world phone,” allowing people to use GSM or CDMA networks. However, China Mobile can only support iPhone users on its 2G GSM network (it utilises TD-SCDMA 3G) with China Unicom utilising its 3G WCDMA (Wideband CDMA) network.

With such a long wait for the iPhone 4S to launch in the country, only for Apple to halt sales on launch day, questions will be asked over why it wasn’t noticed before the device went on sale.