The Waikato District Health Board is denying that a significant number of its staff have been bullied or harassed.
More than a third of its 1500 workers who filled in a staff survey last year said they had been bullied.
The Nurses Organisation believes it is much worse, saying almost all of its 2500 nurses at Waikato Hospital have made similar complaints to the union.
The union's education officer Selina Robinson says most of her members feel overworked and under extreme pressure at work, but are too scared to speak out.
Ms Robinson believes there is a culture of blame, which comes from the top of the health board.
But DHB chief executive Craig Climon said on Friday that, regardless of the number of complaints, they are responding with education and training programmes that will benefit everyone.
"A culture of blame - if it does exist - is counter-productive, from my point of view. We need everybody to be active around quality improvement. If people are going to be blamed for every mistake they make, issues will go subterranean."
Mr Climon says Waikato is no worse than any other district health board, and the story has been blown out of proportion by the media.