All-night gaming marathons will soon end for some Chinese kids after internet giant Tencent began limiting daily playing times on its smartphone smash hit King of Glory on Tuesday to "ensure children's healthy development".

Young players will be restricted to one or two hours on the mobile online multiplayer battle game, which boasts 80 million daily users, as concerns grow in China that long periods online are posing a serious threat to the health of the country's youth.

Tencent, which ranks first in the world for gaming revenue, said in a statement that King of Glory was "supposed to bring joy ... but excessive gaming brings joy to neither players nor their parents".

State media reported in April that a 17-year-old gamer in southern Guangdong province suffered a type of stroke after spending 40 consecutive hours playing King of Glory.

The game became the world's highest grossing game this year, with estimated first-quarter revenue of around 6 billion yuan ($882 million), according to Xinhua News Agency.

Users under 12 years old are now limited to one hour of play a day, and will not be permitted to sign in after 9 pm, Tencent said in a statement over the weekend. The move went into effect on Tuesday.

Users between 12 and 18 years old are limited to two hours per day.

According to the company, which called its new controls the "three broad axes", those who play beyond the allotted time period will be "forced to go offline".

Tencent will also place caps on the amount of money that underage users can spend on the platform, so as to rein in "minors' irrational consumption".

Additional measures implemented earlier this year include a real-name authentication system and software that enables parents to place electronic locks on the game.

China introduced draft legislation in February this year that would ban minors from playing online games between midnight and 8 am.

But Tencent said that in the current absence of "clear regulations to guard against mobile gaming addiction, we have decided to take the lead ... and dispel parents' concerns".

"We also call on parents to spend more time with their children," it added.

Agence France-presse