This picture shows the Opera House illuminated in the colours of the Aboriginal flag in Sydney on Australia Day on Jan 26, 2023. (PHOTO / AFP)

SYDNEY - Senior Indigenous leaders on Thursday criticized Australia's main opposition party's "Judas betrayal" for declaring it would campaign against a proposal to constitutionally recognize the country's Aboriginal and Torres Island people.

Liberal Party leader Peter Dutton announced on Wednesday the party would campaign against a national vote to enshrine an Indigenous consultative body in the constitution, dashing hopes of bipartisan support on the issue.

Noel Pearson, an Indigenous leader and a key campaigner for the community, said he had a sleepless night after hearing the decision of the Liberal Party.

"I was troubled by dreams and the specter of the Dutton Liberal party's Judas betrayal of our country,” he told ABC radio. "It is a sad day for the country."

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Australians will be asked to vote in a referendum later this year on whether they support altering the constitution to include a "Voice to Parliament", a committee to advise the parliament on matters that affect the lives of its Aboriginal and Torres Strait Island people.

This is about whether we as a country can be optimistic, can be enlarged, can come to terms with the fullness and richness of our history, can express our pride in sharing this continent with the oldest continuous culture on earth, or whether we shrink in on ourselves.

Anthony Albanese, Australia's Prime Minister

A successful referendum would finally give constitutional recognition to Australia's Indigenous people, who track below national averages on most socio-economic measures and suffer disproportionately high rates of suicide, domestic violence and imprisonment.

Aboriginal and Torres Strait Islander people, who represent about 3.2 percent of the country's population of nearly 26 million, are currently not mentioned in its 122-year-old constitution.

Uluru Dialogue spokeswoman and Indigenous leader Pat Anderson said the Liberal decision was a vote for “business as usual”.

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"Legislative bodies have come and gone; only constitutional enshrinement will guarantee First Nations peoples will have an enduring say and ultimately improve First Nations lives," she said.

Prime Minister Anthony Albanese's government has staked significant political capital on the referendum, but no referendum has succeeded in Australia without bipartisan support.

There have been 44 proposals for constitutional change in 19 referendums since Australia's independence in 1901, and only eight of these proposals have been approved.

Speaking to the media on Thursday, Albanese described opposition leader Peter Dutton's stand as "divisive" and "opportunistic".

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"This is about whether we as a country can be optimistic, can be enlarged, can come to terms with the fullness and richness of our history, can express our pride in sharing this continent with the oldest continuous culture on earth, or whether we shrink in on ourselves," he said.