Ms Onus-Williams was an early member of ongoing treaty talks in Victoria.
She was appointed in 2016 to the Victorian Aboriginal Treaty Working Group,as a nomination of the Koorie Youth Council,but is no longer involved in the treaty process,which was set up between Aboriginals and the Andrews government.
Ms Onus-Williams is an executive member of the youth council,which is funded by the state government and promoted Friday’s protest organised by the Warriors of the Aboriginal Resistance.
She is also a descendant of acclaimed Indigenous artist Lin Onus and renowned Aboriginal activist William Townsend Onus.
Police monitor the 'Invasion Day' rally.Credit:Chris Hopkins
Ms Onus-Williams said she understood her comments may have caused offence,but did not want them to draw attention away from the estimated 60,000 people who flooded the streets of Melbourne's CBD in solidarity with Aboriginal people.
"It was the biggest protest for Aboriginal people since the 1970s and I am just so proud of our community and of everybody else who came out with us today,"Ms Onus-Williams said.
"I would hate my comments to deflect from that."
Many of the marchers dressed in black to symbolise the mourning felt by the Indigenous community.
Friday marked 230 years since the establishment of a British colony in Australia and the demonstration remembered the 80th anniversary of the first"day of mourning"in 1938,when Aboriginal people walked in silence to protest the"callous treatment of our people by the white man".
A spokesperson for Greens MP Lidia Thorpe,the state's first female Aboriginal elected to Parliament,declined to comment on Ms Onus-Williams'words but said:“January 26 is a painful day for our people,we’re hurting. It’s painful to see people celebrating while we’re in mourning.”
A spokesman for Victorian Premier Daniel Andrews said while everyone had the right to express their view it should always be done peacefully.
"That’s one of the great things about our democracy and what we celebrate on Australia Day,"he said.
Opposition Leader Matthew Guy,however,said Ms Onus-Williams’ words were a''disgrace''.
He also attacked the Greens and Labor for opposing celebrating the day on January 26,although Buninyong MP Geoff Howard is the only member of the Andrews government who has said publicly that the date should change.
“The Greens and Labor left-wing opposition to Australia Day is an example of just how out of touch these people are with mainstream Australians,” Mr Guy said.
The organisers of the'Invasion Day'rally have been contacted for comment.