A doctor who failed to adequately examine an Aboriginal woman who died of sepsis in police custody the following day has been fined $30,000 for professional misconduct.

Yamatji woman Ms Dhu, whose first name is not used for cultural reasons, was originally taken into custody at South Hedland Police Station in August 2014 over unpaid fines totalling $3600.

After she complained of pain in the lower right rib region, police took the 22-year-old to the ED at the Hedland Health Campus where one of the other doctors diagnosed behavioural issues and discharged her back into police custody.

The following day she was taken back to emergency with rib pain and shortness of breath.