Apple Inc is facing closer scrutiny from two government agencies in China for allegedly failing to follow the nation's rules on product warranties, after media reports questioned the US company's customer service.

On Thursday, the State Administration of Industry and Commerce said it had instructed subordinate agencies across China to step up supervision of electronics companies. It specified Apple by name. It and other firms are accused of applying their own terms to customer-service contracts, in violation of Chinese laws and regulations.

The administration is the second Chinese agency in two days to level criticism at the iPhone and iPad maker.

On Wednesday, the General Administration of Quality Supervision, Inspection and Quarantine, which is tasked with formulating standards in China, told Apple to change its service practices and follow Chinese laws and regulations. It was responding to complaints from consumers who said Apple provides only one-year warranties on the mainboards of its MacBook Air computers sold in China.

Chinese rules require manufacturers to provide a two-year warranty on a computer's major components.

China is an important market for the California-based electronics giant. Sales in the country were $6.8 billion, about 13 percent of Apple's worldwide total, in the fiscal first quarter that ended on Dec 29.

The US company has come under fire from Chinese regulators and media since China Central Television on March 15 aired a report criticizing Apple and German automaker Volkswagen AG, among other foreign and Chinese firms, for allegedly violating consumer-protection laws.

In CCTV's two-hour program, Apple was accused of treating customers in China differently from those in other countries. Some users complained that when their iPhones were broken, they returned them to Apple for a free replacement - the company generally prefers that to providing repairs - but were then charged a fee for a new back cover of their device. Customers in the US and elsewhere get free phones, back cover included.

Others in China said their iPhone warranties didn't begin anew once the new device arrived, thereby shortening the warranty period - in contravention of Apple's practices in the US.

Apple China, which typically waits for guidance from its US parent, issued a brief statement the day after the CCTV program. Without directly responding to the televised allegations, the company said it had been "striving to exceed consumers' expectations" and valued customers' "criticism and suggestions".

The following week, Apple China released another statement, this time confronting the claims from the TV show. The company said Chinese consumers enjoy its highest standard of service and that warranties on its products in China have about the same terms as in the US and other parts of the world. The statement said Apple does make some adjustments for Chinese laws and regulations, such as not using refurbished parts.

It cited Chinese regulations stating that a device has only 30 days of warranty coverage, but Apple users get 90 days.

The latest statement, however, didn't placate some Chinese media outlets. Some reports chided the company for not directly addressing customers' complaints.