New figures released by the Penington Institute show there were 85 "unintentional overdose deaths" in Newcastle between 2014 and 2018 - up from 49 in the five years between 2009 and 2013.

"That's an unacceptably high number - and it's 85 too many," John Ryan, the chief of Penington Institute, said.

"The data is clear: the overdose situation in Newcastle is worsening."

According to the "independent drug policy organisation's" Annual Overdose Report, 524 NSW residents lost their lives to unintentional overdoses in 2018 - the equivalent of approximately one person dying every 18 hours.

While in other states, illicit drugs like heroin and ice were most often implicated in overdose deaths, the report found it was pharmaceutical opioids and benzodiazepines - which the Institute described as "Australia's silent killer" - driving deaths in NSW.

Benzodiazepines, commonly used to treat anxiety and insomnia, were the drug type most often detected in unintentional overdose deaths in the state, with 198 deaths in 2018 alone.

According to the Penington Institute, accidental drug overdose deaths were up in areas right across the Hunter, with the exception of eastern Lake Macquarie, which dropped from 28 deaths in 2004-2008 to 23 in 2014-2018. The report showed that since 2010, rural and regional NSW had experienced higher rates of unintentional overdose deaths than Greater Sydney.

As of 2018, rural and regional NSW had a rate of 7.9 unintentional overdose deaths per 100,000, compared with six per 100,000 in Greater Sydney.

Between 2014 to 2018, the overdose death rate per 100,000 was 7.7 in the Hunter and Central Coast Primary Health Network.

Penington Institute released the Annual Overdose Report on International Overdose Awareness Day.

The report said more than 2000 Australians died of overdose in 2018, with deaths involving opioids, stimulants and the use of multiple substances at the same time.

It found more than 40 per cent of all unintentional overdose deaths in 2018 were suffered by people aged 50 and over, while those aged in their 40s accounted for 27 per cent of the total.

"People are suffering and dying unnecessarily and all levels of government and society are not doing enough to keep them safe," Mr Ryan said.

"This is Australia's hidden health crisis. We're looking to start a conversation, bring overdose out of the shadows and ultimately reduce harms."

Mr Ryan said it was "absolutely unacceptable" that for five years running, more than 500 people in NSW had died because of overdoses.

"The persistence of these numbers suggests one thing above all: we are not doing enough to lessen the harms of drugs in our largest state," he said.

"Not enough Australians understand the potential risks of drugs you can get from your doctor or from the pharmacy around the corner and importantly the dangers of combining drugs."

Professor Geoff Isbister, from the clinical toxicology research group at the University of Newcastle, questioned whether the Penington Institute had combined "accidental" overdose deaths with "undetermined" deaths from government data to determine the results of its report.

If that was the case, the numbers potentially included incidents of deliberate self harm too.

"The term 'unintentional overdose' is confusing, and without having more detailed information in terms of the cause of the poisoning, it is hard to comment on," he said. "I'd be concerned that there are intentional deaths there that have been missed because it can be hard to classify."

Professor Isbister said the report only looked at deaths, but a "much larger" issue was trying to help those who deliberately self-harmed or self-poisoned.

"Measurements of death are just the tip of the iceberg," he said. "It's the rest of it, it's the non-fatal overdoses - that is where we need more services in terms of providing expert toxicological advice, and in terms of providing mental health services to support people."

Professor Isbister said clinically, they were certainly seeing more presentations for prescription drug overdoses - such as opioids and benzodiazepines - than the "classic" street drug overdoses, such as heroin.

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