An Aboriginal woman felt "like dirt" as she was turned away from Queensland's Parliament House for wearing her people's flag on a T-shirt.

Janine Kelly was blocked from the state's democratic centre on Tuesday morning as she tried to show her support for a police appointment to address overrepresentation of Aboriginal people in custody.

A little more than 110 petitioners wanted a second Commissioner of Police appointed, with the requirement that person must be an Aboriginal or Torres Strait Islander.

When she arrived at George Street on Tuesday morning, Ms Kelly was told she couldn't enter because of the flag on her T-shirt.