And while a magistrate wasn't convinced Bakarich also said "This is what mixed martial arts does to you", he rejected a self defence claim made by the high-profile owner of two methadone-dispensing pharmacies when the matter went to court in 2017.

Bakarich "snapped" on both occasions, but was not an angry man, the NSW Civil and Administrative Tribunal said on Friday after finding him guilty of professional misconduct.

But in "snapping" and acting aggressively Bakarich posed an unknown risk if confronted by an aggressive or demanding patient, the tribunal said before cancelling his registration.

"While the risk posed is low, it is nonetheless real," the tribunal said.

Bakarich was first charged with assault in July, 2014 after a fight in a hotel while drinking with three other people. The four were thrown out and another fight occurred, with Bakarich punching a man until he fell to the ground, and then kicking the man in the head and body.

When a woman tried to intervene Bakarich punched her in the face. He was convicted of the assaults in January, 2015 and given a two-year good behaviour bond, but did not report the matters to health regulators.

In September, 2016 he was working at his Hamilton South business, Nic's Pharmacy, after 7pm when a former customer on the NSW Opioid Treatment Program, who was banned from the pharmacy a month earlier for hostile behaviour, appeared acting aggressively.

Police heard two versions of what occurred that night. Bakarich said he ran out to a man he thought was having an overdose and was "jumped" by the man and two others.

The former customer denied acting aggressively and told police Bakarich walked towards him saying "Come on, let's do this. I'm going to sort you out", before jumping on the man and punching him in the face while threatening: "You tell anyone. I'll come f... you up".

A magistrate in May, 2017 believed the former customer who was left with a suspected eye socket fracture and a knocked tooth. Bakarich was ordered to perform 140 hours of community service and placed on another two-year good behaviour bond.

Bakarich again failed a mandatory requirement to report the convictions to health regulators.

It was not until November, 2017 that Bakarich recorded the convictions with the Australian Health Practitioner Regulatory Authority in response to a question when renewing his registration.

By July, 2018 the Pharmacy Council of NSW imposed conditions, including that he not have face-to-face contact with potential, current or former pharmacy customers and not practise without supervision.

In October, 2018 people rallied in Newcastle after Bakarich said his methadone clinic for 350 people was under threat because of changed legislation preventing relocation. But a few months later he was in front of the Civil and Administrative Tribunal fighting cancellation of his registration.

During submissions before hearings in June Bakarich said he would "honestly prefer to go to jail over losing my registration and that's the truth, if I had to choose between the two".

He argued four pharmacies owned by him and his estranged wife provided 285 "dosing positions" to Hunter people on the NSW Opioid Treatment Program, and were under threat of closure if his registration was cancelled.

"He submits it would not be in the interests of either the participating patients or the broader community if his pharmacies were to close, because it would significantly reduce the treatment options available to patients," the tribunal said.

But NSW Ministry of Health principal pharmaceutical officer Alexander Gavrilovic challenged Bakarich's claim that he would not be able to transfer ownership of the four pharmacies to a third party.

The tribunal found Bakarich deliberately avoided notifying health regulators of his second conviction because "unsurprisingly, he was fearful of the consequences for his registration and ownership of the pharmacies".

"In those circumstances, Mr Bakarich's failure to report after the council proceedings amounted to a reckless disregard for his professional obligations," the tribunal found.

The tribunal accepted a psychiatrist's assessment Bakarich was probably suffering from post-traumatic stress disorder during the assaults, relating to "extensive and severe" physical violence and emotional abuse as a child from the man he thought was his father.

The 2014 assaults occurred shortly after Bakarich learnt his biological father committed suicide when he was a baby.

The tribunal was told Bakarich had "unresolved anger issues" but the Health Care Complaints Commission challenged his claim he was "doing everything in his power" to address them.

The tribunal found the criminal and disciplinary proceedings were likely to act as a powerful deterrent against further acts of aggression but rejected his submission to impose a fine.

Unless and until he received ongoing and regular anger management treatment there remained a risk of further aggression, the tribunal said.

The cancellation comes into effect on December 10. Bakarich was ordered to pay 70 per cent of the commission's legal costs.

Editor's note: An earlier version of this article included a reference to Newcastle MP Tim Crakanthorp providing a letter of support to Bakarich.

Mr Crakanthorp wrote a letter in September, 2015, at Bakarich's request, supporting Bakarich's application to increase the maximum number of 50 patients he was able to treat under the pharmacy opioid pharmacotherapy.

Mr Crakanthorp had no knowledge Bakarich was convicted of assaulting two people, including a woman, in January, 2015.

He had no knowledge the September, 2015 letter was tendered to the NSW Civil and Administrative Tribunal by Bakarich during proceedings against Bakarich in 2019, and under circumstances where Bakarich was facing professional misconduct charges for failing to report to health regulators that he had been charged and convicted of serious assaults against three people, including a woman.