Peter Dutton has been accused of using race to divide the nation and win votes against the Indigenous voice.
Greens leader Adam Bandt said his party would have preferred the government prioritised a treaty with Indigenous people but would back the voice regardless.
He said Mr Dutton was denying justice to Indigenous people with his opposition to the voice.
“The leader of the opposition has taken this opportunity to divide instead of unite, to continue a long tradition of seeking to use race to win votes,” Mr Bandt told parliament.
“The Greens want to see the voice succeed not only because it is a key element of the Uluru statement, but because failure will take us further away from truth and treaty.”
Debate on the referendum continued into the night, with the Liberals and Nationals speaking against the constitutionally enshrined body.
Ahead of the debate, Nationals leader David Littleproud told colleagues mistakes were made during colonisation but a constitutional voice wouldn’t help, while stressing the need for respectful debate.
Mr Dutton said the Indigenous voice to parliament would take the country backwards, labelling it Orwellian and a reckless roll of the dice.
Mr Bandt said the opposition leader’s rhetoric was dividing the country.
“He’s scared to listen to what a voice might have to say,” he said.
“He’s scared of the voice of First Nations people, while he pushes for them to be silenced in prisons.
“If the voice referendum goes down, we’ll be further away from those critical next steps for justice.”
Prominent ‘yes’ campaigner Noel Pearson has warned a rejection of the voice would put an end to reconciliation in Australia.
At an event at Sydney University, Mr Pearson said he still believed there would be a majority ‘yes’ vote but a defeat would set the cause back.
“The reconciliation agenda will have no credibility after this failure, it will evaporate,” he said.
“We will go back to protests and protests and it will be never ending.”
Liberal MP Julian Leeser, who quit the frontbench to campaign for the voice, is pushing to remove “executive government” from the advisory body’s remit.
He believes this could sway some undecided voters including coalition MPs, despite suggestions to the contrary.
Parliament will decide the wording of the referendum question along with the changes to the constitution, should the proposal succeed.
Australians will cast their votes on the voice later this year.
By Dominic Giannini and Andrew Brown in Canberra