A 38-year-old Aboriginal man has died in Hakea Prison in Western Australia.

The man was found unresponsive in a single occupancy cell Wednesday night just after 10pm.

WA Department of Justice said on Thursday that prison and medical staff provided first aid to the prisoner until paramedics arrived.

The Department said preliminary reports indicate the man may have experienced a medical episode.

Noongar justice advocate and Megan Krakouer told National Indigenous Times the death drove home the need for reform.

"We mourn yet another Black death in custody; a heartbreaking reminder that the Labor government continues to ignore the cries of our people and the urgent need for change," she said.

"Over three decades since the Royal Commission into Aboriginal Deaths in Custody, most of its recommendations remain unimplemented. This ongoing inaction is killing our people.

"One clear step the Federal Government must take is to amend Section 19(2) of the Health Insurance Act 1973, which currently excludes Medicare from prisons. This is health discrimination affecting 135 prisons nationwide and disproportionately harms Aboriginal and Torres Strait Islander people.

"Access to proper healthcare is a human right; not a privilege lost at the prison gate. Until Medicare is brought into prisons, this government will continue to have blood on its hands and no conscience. Justice delayed is justice denied."

As is mandatory for all deaths in custody, WA Police will prepare a report for the State Coroner.

More than 600 Indigenous people have died in custody since the Royal Commission into Aboriginal Deaths in Custody brought down its findings and over 300 recommendations for reforms in 1991.

More details to follow.