Michael De Guzman, a registered nurse, is being detained at a forensic hospital after a NSW District Court judge found him not guilty in 2018 of 11 charges by reason of mental impairment.

They included shooting dog squad officer Sergeant Luke Warburton with intent to murder at Nepean Hospital in January 2016.

The police officer was shot with his own gun as he tried to take scissors from the hand of de Guzman, who had seconds earlier held a doctor hostage and made threats to kill.

At the time of the shooting, de Guzman was convinced his wife had been taken to Saudi Arabia to join a Russian mafia-run prostitution ring and people in the hospital were involved.

The Health Care Complaints Commission subsequently took disciplinary proceedings against him in the NSW Civil and Administrative Tribunal.

The tribunal on Friday cancelled his national nursing registration and banned him from seeking a re-instatement order for five years, the period sought by the HCCC..

"We are cognisant that the practitioner expresses a wish to be able to practise in the future and at a time sooner than proposed by the HCCC," the tribunal said.

It upheld all three complaints against de Gruzman, which he admitted.

He was found to have engaged in improper or unethical conduct by purchasing and using methamphetamine between 2012 and 2016 when he was working as a nurse.

Secondly, he suffers a mental illness impairment, amphetamine use Disorder and schizophrenia, with significant potential for relapse.

Finally, he was found guilty of professional misconduct and not competent to practise.

The tribunal was told he was making good progress and not using substances while in custody, but will require ongoing rehabilitation and treatment in the hospital where he will likely stay for a number of years.

An expert referred to the fact de Guzman had been using ice on a daily basis while working as a nurse.

"The effect of the ice use on his mental state was ultimately catastrophic, led to police officers and medical personnel and health professionals being seriously injured and traumatised, and resulted in serious adverse publicity for the nursing profession."

The expert said his conditions were in remission, that he is not currently symptomatic, and in the ordinary circumstances, subject to a considerable number of safeguards, he could practise.

"It is unlikely that he will be at the point where he could have his registration restored with conditions for many years," he said.

"If and when(he) reaches this point, there will be significant recency of practice issues and at that point he will require significant retraining."

The tribunal accepted the evidence, finding that by his illicit drug-taking, de Guzman potentially exposed patients to ill-treatment and negligent care.

"His actions on 12 January 2016, which we are cognisant did not occur in the practice of his profession or the purported practice of his profession, have had terrible and lasting consequences for those who suffered injury from his conduct.

"His actions on that day brought the reputation of the profession into disrepute and support a finding that he is not competent to practise."

Australian Associated Press