By Maeve Bannister and Andrew Brown in Canberra

CAMPAIGNERS for an indigenous Voice remain confident of success at the upcoming referendum despite declining support in new opinion polling.

The latest Newspoll shows 46 per cent backing for the proposal, dropping from 54 per cent earlier this year.

Some 43 per cent of those surveyed were opposed and 11 per cent did not know.

The referendum, due to be held between October and December, needs a national majority as well as a majority of voters in at least four states for the constitution to be changed.

But Yes 23 campaign director Dean Parkin said he expected support to grow for the voice as it moves away from political debate in parliament and into communities.

“It’s understandable in some ways that there has been some tightening up in the numbers. We knew this would always become contested,” he told Sky News.

“The conversation has been bogged in Canberra in politics, in a fair bit of negativity there.”

Mr Parkin said the Newspoll results differed from those found when talking to people in the community.

“It’s quite encouraging actually when you get out into the community. That goodwill we’ve talked about for a long … time is absolutely still there,” he said.

“There’s five months between now and when we think the referendum will be had.

“We think there’s plenty of time between now and then to actually have that conversation with more Australians.”

The Newspoll showed women voters mostly in favour of the ‘yes’ side, 47 per cent to 40 per cent against.

Among males, 46 per cent were in the ‘no’ camp while 45 per cent backed the ‘yes’ side.

Former ACT chief minister Kate Carnell, who is leading a Liberals for ‘yes’ campaign, said support would ramp up once referendum legislation passes the Senate later this month.

“We’ll be able to move the campaign where it should be and that’s down to grassroots Australia where it should be,” she told ABC Radio on Monday.

“Really, this shouldn’t be a political debate at all.

“It should be a debate out there in the community. It’s every Australian that needs to vote on this.”

The Liberals group is made up of Ms Carnell, former NSW premier Mike Baird, Tasmanian Premier Jeremy Rockliff, ACT Opposition Leader Elizabeth Lee and federal backbenchers Julian Leeser and Bridget Archer.

Ms Carnell said the constitutional changes proposed were safe options and would bring the country together.

“The message is, if we just keep doing the same thing in this space, we’ll end up with the same outcomes,” she said.

“Liberals, I hope, will be focused on on getting practical change.”

The federal Liberals support constitutional recognition of Indigenous people but want parliament to legislate local and regional voices.