Apple products have gained huge popularity in China over recent years. iPhones and iPads are the "must-have" accessory, particularly in urban areas while the company's stores are often overflowing with customers trying out the latest gadgets.

But there's now a scandal brewing over Apple's warranty and repair policy, and concern that Chinese consumers are being given a rough ride.

In a recent interview, Apple CEO Tim Cook said China will soon become Apple's biggest market.

Just walk past any Apple store, and that's certainly how things seem to be going.

But voices of complaint are coming from some Chinese consumers, over Apple's after-sale service.

The company offers a global warranty period of 1 year - that's the same whichever country you are in. But Chinese law states that warranties on computer sales MUST be at least two years.

Ge Youshan, Lawyer, said, "Foreign companies in China should obey Chinese law. If their clauses are better than Chinese regulations, that's ok. But in this case, Apple's warranty clauses apparently violate China's laws.

But the biggest complaints have been about HOW Apple goes about repairing its products.

In the US and the UK, defective iPhones can be replaced by a brand-new one during the one-year warranty period.

In China, consumers can have the electronics replaced but not the outer-casing. Some think that's unfair.

In an announcement on its website on Saturday, Apple denied discriminatory practice in China.

But the company didn't refer to the specific allegations over the non-replacement of the outer casing.

Last year, Apple was forced to modify the terms of its after-sales service in South Korea, after a customer sued the company for replacing her defective iPhone with a refurbished one. Some Chinese netizens have called on Chinese consumers to mount a similar challenge.

Apple sales in China increased by 67% in the first financial quarter of 2013. The company's annual income growth in China, including Hong Kong and Taiwan, is more than twice that of Japan, and also exceeds the US and Europe.

It remains to be seen whether this global tech giant will be pressurized to respond to the complaints, as it's China market becomes an ever-bigger part of its global operation.