China's star swimmer Sun Yang has been "punished for breaking a series of team rules," according to the Zhejiang College of Sports.

The southeastern Chinese college, to which the two-time Olympic champion is affiliated, accused Sun of a lack of discipline, head of the college Li Jianshe told CCTV in a telephone interview.

The college asked the 22-year-old to reflect on what he has done in a stern statement issued on Monday, after Sun asked for a new coach and was rumored to be involved with a stewardess. He also stayed out all night instead of focusing on his training, according to Beijing Times.

The college also withheld a month of Sun's allowance and "provisionally suspended" him from all social and commercial activities, including personal endorsements, the college head said.

Beijing Times said Sun Yang went to Zhejiang College of Sports to apologize to his coach Zhu Zhigen, but Zhu was not there, Feb 4, 2013. [Photo/CFP]

The 10-year relationship between Sun and his coach Zhu Zhigen turned sour after the swimmer reportedly asked for a new coach. The 56-year-old coach disapproved of Sun's relationship with an air stewardess, which has not been confirmed by Sun himself, as Zhu believed it will disrupt Sun's concentration on training.

Zhu is also afraid that too many commercial activities may take a toll on Sun's swimming achievements as the rising star gets commercial endorsements of many famous brands after his London Olympics triumph.

Sun has been away from systematic training for over 40 days, and a scheduled training program in Australia after the Chinese Spring Festival will have to be canceled or postponed because of Sun's shoulder injuries, said an unnamed official at the sports college.

"This place is for good athletes, not for athletes with privilege," said Li Jianshe. "Although Sun Yang has realized what was wrong with him and he promised to put it right, we have to punish him as everyone is equal when it comes to rules."

"Zhu has been coaching Sun Yang for 10 years and I don't think their bond is so fragile," said Li.

Neither Sun Yang nor coach Zhu Zhigen has responded to the announcement so far.

Sun is one of the most famous sports stars in China after winning two gold medals at the London Olympics.

He was just crowned last month, with his fellow swimming teammate Ye Shiwen, as the Sports Personality of the Year 2012, overpowering badminton superstar Lin Dan and two-time Olympic boxing champion Zou Shiming.

Beijing Times said Sun Yang went to Zhejiang College of Sports to apologize to his coach Zhu Zhigen, but Zhu was not there, Feb 4, 2013. [Photo/CFP]

Related photos:

Madame Tussauds Shanghai museum unveils Sun Yang's wax figure

Related stories:

Sun Yang, Ye Shiwen named Sports Personality of Year

Sun Yang wins in national swimming championship