Victorian senator Lidia Thorpe is quitting the Greens and will move to the crossbench.

In an announcement Monday afternoon, Senator Thorpe said she was quitting because of Greens MPs and members who have raised support for the Voice, while Indigenous community activists have raised concern about having a Voice before Treaty.

While not formally opposed to the Voice, Senator Thorpe has made her stance clear on welcoming Sovereignty and pursuing Treaty.

During the announcement Senator Thorpe said she wanted to better support "strong grassroots Black sovereign movements" within the country.

"I want to represent that movement fully," she said.

"It has become clear to me that I can't do that from within the Greens.

"Now, I will be able to speak freely, on all issues from a sovereign perspective without being constrained by portfolios and agreed party positions."

Despite quitting the Greens, Senator Thorpe did not announced her final official stance on the Voice.

"This is the message delivered on the streets on January 26 full stop. This was the movement I was raised in, my elders marched for a treaty. This is who I am," Senator Thorpe said.

"I am not announcing my final position on the Voice today. I want to continue my negotiations with the government."

Senator Thorpe continued by thanking the Greens party and leader Adam Bandt before concluding her speech.

The Gunditjmara, Gunnai and Djab Wurrung senator was the Greens federal spokesperson on Indigenous policy.

As Senator Thorpe won re-election at the last election she is able to remain in parliament as an independent without contesting an election until 2028.

Mr Bandt, alongside deputy Greens leader Mehreen Faruqi and Greens leader in the Senate Larissa Waters, is due to speak at 1:45pm AEDT.