The survey results, released by Newspoll on Sunday, also show the divide growing between men and women, old and young, and those living regionally compared to their urban counterparts.
Just 46 per cent of the 1,549 people surveyed said they would vote yes, with 43 per cent planning to vote no and the remainder unsure.
Women, younger voters and people with higher levels of education were more likely to be supporters of the proposed constitutional amendment, while men and those over 50 firming against the change.
Dutton 'duplicitous' in Voice argument
The dwindling support for the Voice will come as sobering news for the yes campaign as the country heads for an expected vote in the latter half of the year.
With the political battle lines drawn, the war of words between yes and no supporters has ratcheted up in recent weeks.
Prominent Voice supporter Noel Pearson took Opposition Leader Peter Dutton, now de facto leader of the No campaign, to task on Sunday for his 'duplicitous' and 'dishonest' approach to the debate.
“I met with him two or three times ... and at those meetings, Peter was very, very clear in what he said to me," Pearson told Sky News.
"He said ‘I do not agree with the race argument. Don’t take me to be making a race argument’.
He assured me that he did not take the Voice to be racial proposition. But of course ... he has come back to make this completely dishonest argument about re-racialising the Constitution
"I think he’s being a bit duplicitous now in talking about re-racialising the Constitution.”
The House of Representatives passed. During debate, the Liberal leader said the Voice "will permanently divide us by race".
NAIDOC committee affirms support
Meanwhile, the NAIDOC committee became the latest organisation to publicly support the Yes campaign.
Referring to this year's NAIDOC theme of 'For Our Elders', the statement, released on Sunday, recognised the differing opinions within communities, but encouraged people to vote for the Voice.
"Through our Elders' teachings we must ensure that when it comes to future decision-making for our people, there is nothing about us, without us."
"As a committee, this year we pay homage to our Elders and we encourage you to use your vote to do the same."
