The Chinese military is fretting about the growing number of would-be recruits failing its stringent fitness test, but says it has the answer: avoid masturbating and playing computer games.

People's Liberation Army chiefs aim to ensure that applicants are in tip-top condition to join the rank and file of the world's largest military force.

This month the official PLA Daily spelt out on social media 10 reasons why so many potential recruits fall at the first hurdle.

It said 20 percent were overweight while eight percent were refused because they had an enlarged testicular vein.

The newspaper did not spell out how army officers knew about the vein issue but said the problems were caused by too much masturbation, too much time playing video games and not enough exercise.

Obvious or oversized tattoos were also a no-no, it said, pointing out that others failed the test because of liver problems associated with too much alcohol.

The PLA Daily said that in one city alone more than half the candidates were rejected after failing to show they were fit and healthy enough.

Beijing said the PLA had high standards.

"China's recruitment process has strict rules and procedures," the defence ministry said in a statement.

"The quality of our recruits is guaranteed and the headwaters of our military will flow long and strong."

Since coming to power in 2012 President Xi Jinping has trumpeted the need to build a stronger combat-ready military, while leading efforts to centralise the Communist Party's control over it.