"It was a fascinating time," Mr Frater said. "The relationship between governance and executive management was not flash. It created an extraordinarily difficult time for the organisation to work through and remain focused, without being diverted by all of that stuff that was going on.
"I wouldn't want to go through it again, but it was an experience you couldn't learn particularly well from a text book."
Originally a laboratory scientist, he became a histologist and worked in pathology at Wellington Hospital. After moving into administration he became COO for Hutt Valley DHB for six years before accepting a six-month contract at Hawkes Bay DHB which became permanent.
By reining in spending and "budgeting wisely" the Hawke's Bay swung into surplus under a revitalisation programme.
"That got us out of the mire," Mr Frater said.
It enabled capital works. The highlight of his time with the DHB being an operating theatre, renal unit, mental health unit and Wairoa Hospital's upgrade.
"We have great people, very committed, and as we have progressed staff have become less cynical - we are getting more people reflecting positively on the reinvestment into the system."
He said his role was mainly one of communicator - he got more work done in quick conversations in hospital corridors and other people's offices than he did in his own office.
Clinical director of acute and medicine services, Dr Malcolm Arnold, said he was engaging, a good all-round Kiwi bloke and probably the most respected COO in the country.
Senior medical specialists in hospitals often had antipathy towards managers, he said.
"We often think of it as us and them, but Warrick seems to provide more of a bridge than many other managers ..." he said.
"If you're not in the middle of something he will stop and chat and see how things are going.
"He sympathises with the situation we have but realises the job he has to do - he seems to carry out both very well although it must be immensely difficult. He is getting pressure from the ministry and his boss.
"He seems to have a way of engaging people in getting the best out of them, without flogging them. He encourages them rather than insisting on things being done. He is collaborative rather than instructive and certainly not dictatorial. He is a very good people manager ... he is very solution based.
"Certainly the whole organisation at the moment is taking on a much more of a collaborative approach, they are involving clinicians and managerial decisions and they are asking us what we think rather than just telling us what to do."
The DHB's guiding programme is Transform and Sustain, aiming to consolidate gains while developing infrastructure and service levels thanks to consistent budget surpluses.
Mr Frater said through prudent choices the DHB had more doctors than it did 10 years ago, despite a constrained financial environment and a steady increase in Emergency Department presentations.
An improved team of clinicians attracted further talent.
"We have re-established our reputation with the wider public throughout New Zealand as a good provider of health services, with a clear direction, that knows where it is going and is in control.
"I think that reputation has spread widely so we are now attracting good calibre people to positions we advertise.
"We have grown the number of neurologists and respiratory physicians. We have expanded our renal service, attracted a very good vascular surgeon and grown the number of general surgeons on our team."
He said it was a complex job, "extremely diverse and challenging". The challenging part was drawing a line at the level of care provided and working with "a very intelligent and diverse work force".
"They have all got views, expectations.
"Melding all of those into a cohesive team to deliver the right care that is needed, every time, is challenging.
"We would like a bigger range of services to meet absolutely everybody's needs, whenever we possibly can - that's not always possible in a resource-constrained environment."
He is proud of the DHB's partnership with private Royston Hospital - many DHBs only used private hospitals as a stop-gap measure, an expensive way of meeting targets.
With a unique long-term contract both patients and organisations benefited, but sometimes demands defeat plans and surgery targets sometimes elusive despite extensive use of Royston. So far this year it is above target.
"It's a team effort - it takes commitment, it takes focus and a degree of resoluteness."
He said a clinician's role in governance was "a major step forward from authoritarian management".
The DHB was leading the country with organisations such as the Clinical Council and the Consumers' Council taking part in governance.
"It has been a very good move and a sound investment."
Approaching 66, but not yet ready to retire, he plans to do some consultancy and project work in the health sector.
He is happy with his achievements but said any organisation benefited from new blood at the helm and he is ready for a "less demanding role" allowing for more tramping and fly fishing.
He pauses at length when asked if there will be a void in his life.
"I really enjoy the job. I never have a problem getting up and coming to work.
"I think I enjoy the vibrancy and intelligence of the workforce - being a part of an industry where people make a difference to other people. It is an extraordinarily rewarding job, and even with its challenges and frustrations there's a heck of a lot more that is positive and enjoyable."