Tokyo, Oct 5 (IANS): Japanese labour inspectors on Thursday ruled that the death of a 31-year-old employee of the countrys public broadcaster NHK was caused due to overwork.

Miwa Sado, who worked at the broadcaster's headquarters in Tokyo, logged 159 hours of overtime and took only two days off in the month leading up to her death from heart failure in July 2013, reports the Guardian.

A labour standards office in Tokyo later attributed her death to "karoshi" (death from overwork) but her case was only made public by her former employer this week.

The announcement comes a year after a similar ruling over the death of a 24-year-old employee at Dentsu advertising agency prompted a national debate over Japan's attitude to work-life balance and calls to limit overtime.

Matsuri Takahashi killed herself in April 2015. Labour standards officials ruled that her death had been caused by stress brought on by long working hours.

Takahashi had been working over 100 hours' overtime in the months before her death, the Guardian reported.

The Japanese government proposes to cap monthly overtime at 100 hours and introduce penalties for companies that allow their employees to exceed the limit.

More than 2,000 Japanese killed themselves due to work-related stress in the year to March 2016, according to the government, while dozens of other victims died from heart attacks, strokes and other conditions brought on by spending too much time at work.