An Indigenous woman who died in custody on Christmas Eve, three days after collapsing at Wandoo Rehabilitation Prison, suffered severe migraines for weeks before she was taken to hospital, her partner has revealed.

Dannielle Lowe, 41, died in Fiona Stanley hospital in the south of Perth after experiencing an unspecified medical episode at Wandoo.

In an exclusive reported Wednesday by Guardian Australia, Ms Lowe's partner, Carrum Mourambine said his partner had told him she had been experiencing "massive migraines".

He said Ms Lowe told him that when she alerted prison staff to the pain she was given Panadol, but he said they took no further action.

"She rang up crying sometimes because she just couldn't take the pain," Mourambine told The Guardian.

Mr Mourambine said Ms Lowe had called him on the day of her death, as she did every morning. Later that day the prison called him and told him his partner was unresponsive and had been taken to hospital. She died three days later.

He said Ms Lowe's youngest child, her three-year-old daughter, was struggling to understand what has happened.

"[She] asked me this morning if we'd go back to hospital and see her," he said.

"Trying to explain to a baby that mummy's passed, it's a very difficult thing to explain to a three-year-old."

Sisters Inside founder Debbie Kilroy told the Guardian prisons needed to ensure detainees received the same level of care that they would on the outside.

Ms Kilroy said Ms Lowe, a mother of eight children, had worked hard to turn her life around, and had completed the prison's rehab program and was due to graduate from the course on Thursday.

"It's clearly distressing for the family… Eight children have lost their mother… women who were in prison with Dannielle are grieving," she said.

"Dannielle was a beautiful person. She was fun. She always helped other women… and she was trying to do everything she possibly could to get out of prison so that she could be with her family and get on with her life in a positive way."

Three days after Ms Lowe's death a 45-year-old Aboriginal man died at Greenough Regional Prison, in Narngulu, also in Western Australia.

The man collapsed while playing basketball at around 4.35pm and died at the scene despite the efforts of paramedics.

A spokesperson for the Department of Justice told National Indigenous Times a coronial inquest must be conducted for every death in custody and both deaths will be investigated.

According to the Australian Institute of Criminology's National Deaths in Custody Program there have been at least 527 Indigenous deaths in custody since the Royal Commission into Aboriginal Deaths in Custody brought down its findings in 1991.

The Commission's 339 recommendations have not been fully implemented.