An Indigenous Australian senator was instructed to retake her oath of office after she changed it to label Britain's Queen Elizabeth as a coloniser.

Greens Senator Lidia Thorpe told parliament's upper house with her right fist raised above her head that she would "bear true allegiance to the colonising Her Majesty Queen Elizabeth II".

The 96-year-old British monarch is also Australia's head of state.

Senate President Sue Lines told Ms Thorpe, a Djab Wurrung Gunnai Gunditjmara woman, that she was required to recite the affirmation - a form of the parliamentary oath that omits a reference to God - as written.

After a pause, Ms Thorpe - a senator since September 2020 who retained her seat at a Federal election in May - recited the affirmation correctly.

Buckingham Palace spokespeople had no immediate response to a request for comment on Ms Thorpe's remark.

Australia's indigenous leaders have fought for generations to win recognition for injustices suffered by their people since European colonisation began in the 1700s.

Prime Minister Anthony Albanese is seeking to make changes to the constitution to recognise indigenous minorities and require governments to consult Aboriginal people on decisions that impact their lives.

On Saturday he unveiled the wording of a draft question for a referendum as part of that plan.