Chinese regulators have reduced the amount of time players under the age of 18 can spend on online games to an hour on Fridays, weekends and holidays.
The move is in response to growing concern over gaming addiction, state media reported.
The rules, published by the National Press and Publication Administration, said users under 18 will only be able to play games from 8pm to 9pm local time on those days, according to the Xinhua news agency.
Online gaming companies will be barred from providing services to them in any form outside those hours and need to ensure they have put real name verification systems in place, said the regulator, which oversees the country's video games market.
Previously, China limited the total length of time that children could access online games to three hours on holiday or 1.5 hours on other days.
The new rules come amid a broad crackdown by Beijing on tech giants, such as Alibaba Group and Tencent Holdings, which has unnerved investors, hammering Chinese shares traded at home and abroad.
The National Press and Publication Administration also told Xinhua it would increase the frequency and intensity of inspections for online gaming companies to ensure they were putting in place time limits and anti-addiction systems.