Dentsu, raided over illegal overtime, was advised to rectify its labor practices in 2010

Advertising giant Dentsu Inc., raided by labor authorities earlier this week in connection with the overwork-induced suicide of a female employee late last year, had been warned in 2010 for illegally forcing employees to work long hours, labor ministry sources told the Mainichi Shimbun.

In August 2010, the Nagoya-Kita Labor Standards Inspection Office issued an advisory urging the Chubu branch of Dentsu in Nagoya to rectify its labor practices, which the labor office deemed to be in violation of the Labor Standards Act.

It had already emerged that the company's Kansai branch in Osaka and headquarters in Tokyo received similar advisories in June 2014 and August 2015, respectively.

Despite repeated warnings from labor authorities, Matsuri Takahashi, 24, a newly hired employee, was pushed to take her own life as a result of overwork in December 2015.

Dentsu acknowledged that its Chubu branch received a warning in 2010. "It's true that our Chubu branch received an advisory to rectify its labor practices. We'll accelerate our efforts to improve the working environment and eliminate long work hours," said an official in the company's public relations division.

The revelations have demonstrated that the company failed to improve working conditions for its employees despite repeated recommendations that the advertising giant correct its labor practices.

The Health, Labor and Welfare Ministry's Tokyo Labor Bureau and other organizations inspected Dentsu's headquarters and its Kansai, Chubu and Kyoto branches on Nov. 7 on suspicion of violating the Labor Standards Act in the overwork-induced suicide.

The authorities suspect that the company, as an entity, forced employees to work illegally long hours.