The annual revenue of Chinese gaming and social media giant Tencent rose 16 percent to 560.1 billion yuan ($88 billion) in 2021, below market estimates of 566.3 billion yuan as the company's chairman calls 2021 a "challenging year."

Tencent's revenue grew at just 8 percent in the fourth quarter, the slowest since it went public in 2004.

"We embraced changes and implemented certain measures that reinforced Tencent's long-term sustainability, but had the effect of slowing our revenue growth," the company's chairman Pony Ma said in a statement accompanying the revenue release.

The internet sector has switched from the fast expansion in pursuit of short-term growth to focus on user value, efficiency of operation and technology innovations, said Ma.

He added that his company will proactively embrace changes to better align itself with the new industry paradigm.

Gaming business

Tencent gets much of its revenue from gaming and develops games such as "Honour of Kings" and "Call of Duty Mobile," said domestic gaming sales grew 1 percent in the quarter ending December 31.

The country has strengthened regulations on younger players since an August editorial last year condemned video games as "spiritual opium." Later that month, regulators limited users under 18 to play video games only from 8 p.m. to 9 p.m. on Fridays, weekends and official holidays. 

The restrictions on minors were effective as the total time spent by minors on its games sank 88 percent in the fourth quarter, Tencent said, adding that the impact of this factor on revenue growth would ease later in the year.

The company added that the time of minors spend on online games accounts for 0.9 percent of the total time spent and 1.5 percent of the total turn-over.

Read more: China's 2021 video gaming revenue growth slows amid tightening rules

China has halted publishing the list of approved new games since August last year.

Tencent President Martin Lau said regulators were still supportive of the gaming industry, adding that the company had a ready pipeline of games for when approvals resumed.

Tencent's gaming sector fared better in the overseas markets. It's fourth-quarter international gaming revenues jumped 34 percent.

(With input from agencies)