A whistleblower has described a "hellish" bullying culture that left her vomiting before shifts at an under-fire health board.
Speech therapist Bethan Mair Williams claimed staff at Betsi Cadwaladr University Health Board (BCUHB) were harassed and were micro-managed.
They were made to complete menial tasks such as hand-washing records, she said.
Adrian Thomas, of BCUHB, said these concerns were being taken seriously and an investigation had been commissioned.
Ms Williams, who no longer works for the health board, was left with a "burning sense of rage and injustice" against the organisation, which has been under special measures for more than five years.
Independent QC Jonathan Walters was commissioned to investigate concerns of another whistleblower in the department.
In a recording of evidence Ms Williams gave to Mr Walters, she was heard fighting back tears.
"It is dispiriting when you work very hard for 20 years for a community and group of people who are extremely marginalised, and you're treated like I've been treated, and many other people have been treated, in this organisation," she said.
"I have a burning sense of rage and injustice about the way this organisation treats people."
Mr Walters wrote a report, but BCUHB is refusing to publish the contents. Ms Williams is appealing that decision.
"It was hellish," she told the Newyddion news programme.
"I am a pretty strong person and I can deal with all sorts of things, but just going into work, it was just - sometimes I just went in, sat in the car for half an hour and went straight to vomit. It still affects me now."
The revelations come weeks after the information commissioner said BCUHB should publish a report into "worrying standards of care" at one of its mental health units, which the health board is appealing against.
Newyddion spoke to other people who worked for BCUHB's speech therapy unit and gave evidence to Mr Walters.
They did not want to be interviewed but confirmed they shared Ms Williams's concerns.
Mr Thomas, the health board's executive director of therapies and health sciences, said: "We've taken the concerns raised seriously and commissioned an investigation, in line with normal health board processes, to look into the issues raised.
"Actions include additional recruitment to clinical posts to increase capacity, service redesign work to improve pathways, referrals and support for both staff and patients, and additional training provided to staff throughout the service.
"A steering group has been established to oversee action on these recommendations, and we have invited the North Wales Community Health Council to nominate a member to join the group."
Ms Williams also made a Freedom of Information (FOI) request calling for a full copy of the QC's report to be published, which was refused on 13 August.
A heavily redacted copy of the 19 recommendations of the Betsi Cadwaladr manager who commissioned the report was released after a separate request was made.
But Ms Williams said staff interviewed wanted their experiences shared to "make sure they had a fair hearing."
"There was nothing secret about this," she said. "What's the point blowing the whistle if no one knows what it is you're complaining about?
"The people of north Wales deserve better than this and those working for Betsi deserve better treatment than what they've received."
Welsh Conservatives' health spokesman, Andrew RT Davies, said: "This is another report by the health board, that's controlled by the Welsh government, that hasn't been made available for consideration.
"And unless you consider the findings of such a report, how can you put things right?"
"Time and time again we're getting examples of things like this coming into the public domain and the health board stonewalling on its response. It's just not good enough."
The Welsh government said it was a matter for the health board.
BCUHB said its reasons for redacting the report's recommendations, and not publishing the report, had been made clear in response to the FOI requests.
"Contributors participated in the report's production with an expectation that their individual statements would be kept in strict confidence," it said.
"To release this information would constitute an actionable breach of confidence.
"The report and summary contain information about individuals, therefore there is the potential risk of identification if we were to release the report, which may then be linked with other information available in the public domain."