Prisoners should be kept 72 hours not 21 days: coroner

Shiralee Tilberoo's family said she was affected by the trauma of the Aboriginal Protection Act era. (Darren England/AAP PHOTOS)

The length of time prisoners can be held in watch houses should be drastically reduced, while funding for organisations supporting people in custody should be boosted, a coroner says.

Deputy State Coroner Stephanie Gallagher made the recommendations in findings of an inquest into the deaths of two women who died of natural causes in Queensland watch houses, with concerns raised about the care and supervision they received.