A 7-Eleven convenience store in Tokyo illegally docked the payment of a 16-year-old part-time worker after she took sick leave without arranging for another employee to cover her shifts, the chain's operator said Tuesday.

The store deducted ¥9,350 from the high school student's paycheck after she took two sick days for a cold in early January, according to Seven & I Holdings.

The store had informed its part-time workers that they must find other workers to cover their shifts when they take unscheduled days off and that they would face penalties if they do not find a replacement.

The operator apologized for the act as it is the employer's responsibility to find a replacement when an employee is unable to work.

The entire amount will be returned to the girl, who has already quit the job.

The pay cut also exceeded the legal upper limit set for a wage penalty, the company added.

"We will make efforts to make all franchisees thoroughly adhere to laws," it said.

The girl took two days off after informing the store that she had caught a cold. She was scheduled to work a total of 10 hours over the two days, according to the Tokyo-based retail giant.

On her pay day last Thursday, she received a paycheck stub stating she was entitled to receive ¥23,375 for working 25 hours, but ¥9,350 — equivalent to 10 hours' pay — was missing.

A note was attached to the document, stating "Penalty" and "¥9,350."