A former Australian soldier suffering from post traumatic stress disorder (PTSD) consulted 28 doctors and obtained 32 drug prescriptions in the months leading up to his death from an opioid overdose, a coronial inquest has heard.

Key points: Matthew Tonkin was declared unfit for active duty after suffering a hip injury

Matthew Tonkin was declared unfit for active duty after suffering a hip injury He was prescribed antidepressants along with opioids to treat his pain

He was prescribed antidepressants along with opioids to treat his pain He became an opioid addict, overdosing at least four times in the year before his death

Matthew Tonkin, 24, was deployed to Afghanistan in 2012 and identified as a "potential leader in the Army", but was significantly affected by the death of his best friend and fellow soldier, Robert Poate, and the maiming of another colleague.

He was later declared unfit for active duty due to chronic pain from a hip injury he suffered during the deployment.

Following his return to Australia, Mr Tonkin was diagnosed with PTSD and was prescribed antidepressants, as well opioids to treat his hip pain.

The WA Coroner's Court was told Mr Tonkin overdosed on opioids four times in 2013 in Queensland, where doctors recorded his dependence on prescription drugs.

Robert Poate's death in Afghanistan had a devastating impact on Matthew Tonkin. ( Australian Defence Force )

He returned to Perth to be near his family in January 2014.

He died in his childhood bedroom at his father's home in July of that year.

'Risk of death' warning

The inquest was told 25 different prescription medications were found at the home at the time of Mr Tonkin's death.

Despite doctors in Queensland recognising Mr Tonkin as an opioid addict who was "at risk of death" in 2013, the inquest heard Mr Tonkin was able to continue to obtain opioids in WA, and was not officially identified as a prescription shopper.

Between January and July of 2014, he consulted 28 doctors at 20 practices, gaining 32 prescriptions from 14 pharmacies.

Mr Tonkin was also alleged to have stolen a prescription pad from a hospital and forged and altered scripts.

Doctors had limited access to Army medical records

One of his treating GPs in Perth, George Crisp, told the inquest he had "very limited information" about Mr Tonkin's treatment while he was in the Army.

Dr Crisp told the inquest that if a real-time monitoring system for prescription drugs had been in place in 2014, it was "very likely [Mr Tonkin] would not have been prescribed a lot of these medications".

Matthew Tonkin had consulted 28 doctors to get prescriptions in the six months prior to his death. ( Supplied: Facebook )

The inquest also heard from Michael Woodall, a psychiatrist who treated Mr Tonkin.

Dr Woodall also said he "lacked any timely information" about Mr Tonkin's medical records and that he recommended his patient submit a freedom of information (FOI) request to the Defence Department as the "quickest way" for his medical history to be obtained.

Coroner Barry King said he found it "odd" and "extraordinary" that Mr Tonkin's medical records did not "follow him" once he left the Army.

'Just the tip of the iceberg', says devastated family

Outside the inquest, Mr Tonkin's father David said the circumstances of his son's death had taken a huge toll on his family.

It's been devastating," he said.

"[Matthew] fought a good fight for a long while, but was unable to carry on after what happened to him over there."

David Tonkin says the family has been hit hard by Matthew's death. ( ABC News: Joanna Menagh )

Mr Tonkin acknowledged there had been some changes to the handling of veterans medical records and post-service care since his son's death, but he said it was happening very slowly.

"There's more and more cases of these problems arising with the many young men that have gone to Afghanistan, and earlier in Iraq, and this is just the tip of the iceberg," he said.

"There needs to be a seamless transition from serving to civilian life and the buck-passing needs to stop."

The inquest is expected to hear from nine witnesses over two days.