Apple can at last begin selling its flagship iPhone 6 and iPhone 6 Plus handsets in China after an industry watchdog approved their use on the country's telecom networks, after being convinced the company had done enough to safeguard users' privacy. China, the world's largest smartphone market, is a crucial one for Apple, and one where it lags behind rivals.

China’s Ministry of Industry and Information Technology, or MIIT, posted an update on its website announcing that the new iPhones would be allowed on China’s wireless networks because Apple had addressed several security issues, which could jeopardize users' personal data, in its mobile operating system. The Cupertino, California-based technology company built features into its iOS 8 to address security concerns related to three background diagnostic tools, to win the regulator's approval.

According to MIIT, Apple said that it will not access users’ data without the regulator's consent and that it will not build a “backdoor” to provide data to government agencies for its products or services. MIIT's other concerns also included safeguarding user data during online payment transactions.

While Apple has not commented on the Chinese ministry’s statement and is yet to announce when the iPhone 6 and iPhone 6 Plus will go on sale in China, some media reports had suggested last week that the new handsets could be released in the country on Oct. 10.

Some people believed that the release of the new iPhones, which hit stores in 10 markets including the U.S., Hong Kong, Japan and Australia on Sept. 19, before releasing in another 20 countries a week later, was postponed as the regulatory approval process in China took longer than expected.

In China, the 4.7-inch iPhone 6 is expected to be priced at 5,288 yuan, or $863, while the 5.7-inch iPhone 6 Plus could cost 6,288 yuan, or $1,026. In the U.S., an entry-level, 16GB iPhone 6 and iPhone 6 Plus are available for $199 and $299 respectively with a two-year carrier contract.

China is considered to be one of the most important markets for Apple, with analysts expecting both the iPhone 6 and iPhone 6 Plus to sell well in the country, where many people prefer smartphones with larger screens, Reuters reported.

Apple reported revenues of $57.6 billion during its holiday quarter in 2013, with $8.8 billion coming from the Greater China region, which includes Hong Kong and Taiwan.

However, Apple is expected to face tough competition from other smartphone manufacturers, such as Xiaomi and Samsung, with the former selling high-end devices for half the cost of an iPhone. According to International Data Corporation, Apple is currently ranked sixth in China and had a 6 percent market share in the second quarter.

Apple announced last week that it sold a record 10 million iPhone 6 units in the first weekend after its launch. Last year, the company had sold 9 million iPhone 5S and 5C models in 10 countries and territories, including China, in the same period.

Last week, Apple opened sales of the iPhone 6 models to an additional 22 countries, including Austria, Belgium, Russia and the United Arab Emirates. The company also announced plans to get the new iPhones into 115 countries by the end of this year.