Police say the cause of death of Melbourne woman Rachael Dixon, 53, who died at a wellness centre in regional Victoria, is unknown.

On Friday evening, police said an autopsy of Ms Dixon's body had been conducted and "at this stage, the cause of death remains unknown". 

"Investigations remain ongoing and police continue to prepare a report for the coroner," a statement said.

Ms Dixon, from Ringwood North in Melbourne's east, died at the Soul Barn retreat in Clunes, near Ballarat last weekend.

Earlier in the week, police said Ms Dixon fell ill after ingesting a drink, believed to be made with mushrooms, late Saturday night and died in the early hours of Sunday, April 14.

Emergency services were called, but local residents were first on the scene and performed CPR on her until paramedics arrived. 

The owners of the Soul Barn venue have said the event Ms Dixon attended was private and did not involve any of their staff.