Doctor's 'grossly irresponsible' prescribing played role in two deaths, coroner finds

A coroner has found a doctor's prescription of drugs had a "direct causative role" in the deaths of two patients. (Supplied: Pexels, CC0)

A coronial report into the deaths of four drug-dependent people has found Dr David Jackson's "grossly irresponsible prescribing" played a direct role in two of the deaths.

A criminal investigation into the deaths resulted in no charges being laid against Dr Jackson.

Coroner Olivia McTaggart has made 10 recommendations, including for the Tasmanian Department of Health to develop a "robust" strategy to refer breaches by prescribers for prosecution.

A former medical practitioner's "grossly irresponsible" prescribing played a direct role in the deaths of two drug-dependent people in Tasmania, a coroner has found.

A report by coroner Olivia McTaggart into the deaths of four people found Dr David Jackson had prescribed methadone as part of opioid replacement therapy (ORT), and benzodiazepines, to each of the deceased at their time of death.

Ms McTaggart also found Dr Jackson displayed a "permissive approach to opioid prescribing" before the deaths, which had raised concerns from medical professionals since the early 1990s.

A lengthy criminal investigation was conducted into the four deaths, and no charges were laid against Dr Jackson.

Nicholas Brown, 35, Toni Wiki, 38, Matthew Winwood, 47, and Belinda Kemp, 37, died within an 11-month period between September 2016 and August 2017.

Ms McTaggart determined the causes of death for each person varied: Ms Kemp died from pneumonia, with mixed drug toxicity, emphysema, obesity and heart muscle disease also contributing, and Ms Wiki's cause of death was cardiac arrest caused by injecting Xanax.

Mr Brown died of combined methadone and benzodiazepine intoxication, while Mr Winwood died from mixed prescription drug toxicity, including methadone.

"He did not play a direct role in the deaths of Ms Wiki or Ms Kemp.

Olivia McTaggart found David Jackson displayed a "permissive approach to opioid prescribing" before the deaths. (ABC News: Luke Bowden)

The coroner said an "intensive, lengthy and large-scale criminal investigation" into the deaths found Dr Jackson's supply of prescribed takeaway doses of methadone was contrary to the governing guidelines, and that his excess supply of methadone to each deceased might have contributed to their death.

Ms McTaggart said investigators had formed the view that Dr Jackson's actions were "grossly negligent" and charges of manslaughter should be considered by the Director of Public Prosecutions (DPP).

The investigation was broadened to