As the summer vacation approaches, the biggest concern for most Chinese parents is what to do with their kids in particular how to stop them squandering money on mobile games.

In early June, a single mother in Heilongjiang province discovered her triplet sons had run up a bill of over 18,000 yuan ($2,700) on her credit card through in-app purchases while playing video games.

A 17-year-old gamer in Guangzhou was diagnosed with cerebral infarction in April after playing the online game King of Glory for 40 hours nonstop.

These are just two of the many cases related to mobile games that have been buzzing on the Chinese internet in recent months.

According to a report by the China Internet Network Information Center, 170 million under-18s have access to the web, with 43 percent spending over an hour a day on tablets and smartphones.

Last year, the total revenue of the online game industry reached 165 billion yuan, an increase of 17.7 percent from 2015.

Yet parents often face big problems when they try to get their money back from game companies. Han Ying, a lawyer who has been keeping an eye on the issue, said proof is the biggest obstacle.

The proof that is often required includes bills, purchase history and even video clips of children playing the games, to prove it is them who paid the money, not the parent, she said.

The authorities have attempted to take stronger action. In January, the State Council released a set of rules to protect minors on the internet, including limiting playing time. The Ministry of Culture also issued a statement in May to beef up the identity registration system of online games to control payments made by children.

However, He Jihua, a deputy to the National People's Congress, the top legislature, found in his investigations that a lot of mobile games had a rather loose ID registration system, and some even teach juvenile players how to get around it.

"The rules and censoring of mobile games should be stricter and more comprehensive," he said.

Deng Lili, a researcher on animation and games at Peking University, said: "Preventing children from becoming addicted to online games is complex. It requires the joint efforts of families, schools and businesses."

Others, though, specifically call for parents to play a bigger role.

Xinhua