The parents of a 31-year-old NHK reporter who died in 2013 due to overwork have criticized the broadcaster for taking so long to acknowledge what happened and urged action to avoid a recurrence.

The death of Miwa Sado was made public only on Oct. 4 by NHK, more than three years after labor standards inspectors determined it was a case of karōshi (death from overwork).

"We have been thinking that NHK has not properly taken responsibility for Miwa's karōshi," her father said at a news conference Friday in Tokyo.