Please note this story contains reference to someone who has died.

The death of an Aboriginal woman in a Brisbane watch house on Thursday has triggered protest across Brisbane, resulting in several arrests.

Queensland Police said in a statement the Ethical Standards Command is investigating the death of a woman in the Brisbane City watch house.

Police said the woman, 49, was found dead in her cell Thursday morning.

She had appeared in Brisbane Magistrates Court on Monday and was remanded in custody on drug and property charges. The woman was awaiting transfer to a correctional facility.

Police said non-profit Murri Watch is providing cultural support and visited the watch house Thursday morning.

Queensland Police Assistant Commissioner Brian Codd said a post-mortem examination had revealed the woman died of natural causes, however he did not know if she requested medical assistance.

Protest has erupted across Brisbane since the death, resulting in the arrests and charges of 18 people.

Starting outside the Magistrates Court and moving on to police headquarters and the watch house in question, protesters blocked traffic and smeared red hand prints across Queensland Police Headquarters on Friday.

The Assistant Commissioner said there had not been a death in custody at the city watch house in its two-decade history until Thursday.

The independent investigation into the death in custody is ongoing.

By Hannah Cross