A ‘yes’ vote for the Indigenous voice would be “all gain and no pain,” the prime minister says, as campaigning efforts intensify in the last week of the referendum.

While more than two million Australians have already cast their ballot for the referendum, the Yes and No camps will ramp up efforts to win over undecided voters ahead of Saturday’s poll.

Two surveys released on Sunday showed the No campaign still ahead a week out from referendum day despite one poll indicating a slight late gain in support for the Yes side in the past month.

A poll, conducted for the Sydney Morning Herald by Resolve Strategic and based on responses from 4728 voters, showed 49 per cent opposed the voice and 38 per cent supported it, with another 13 per cent undecided.

When allowed only a referendum-style “yes” or “no” answer, 56 per cent of respondents opposed the change and 44 per cent were in favour – with the latter up one point since September.

Tasmania was the only state with a majority of “yes” voters, the survey found.

A Newspoll indicated that the No side was backed by 58 per cent while the support for Yes was at 34 per cent and eight per cent were unsure.

The Newspoll of 1225 voters registered a two-point dip for Yes and a two-point increase for No since the previous survey two weeks earlier.

Despite polls showing the ‘no’ campaign ahead, the prime minister said enshrining the Indigenous advisory body in the constitution would be a moment of national unity.

Anthony Albanese added that he wouldn’t pre-empt any polls ahead of Australians hitting the ballot box.

“We have five days in which Australians can have a look at what the question is – the constitutional change is very clear,” he told Nine’s Today Show program.

“There will be a body that may give advice on matters affecting Indigenous Australians and the parliament remains supreme.

“For the parliament and government, the decision-making process doesn’t change but you get better outcomes if it’s an informed decision.”

Earlier he said the referendum did not cost Australians anything to support.

“This is about giving assistance to a group of people, in this case, the first Australians, making up less than four per cent of the population, at no cost to anyone else,” he told a rally in the NSW town of Queanbeyan on Sunday.

“All gain and no pain is what is at stake.”

With just days to go until the referendum, Albanese said he would participate in a nationwide blitz campaigning for the “yes” vote before the October 14 referendum.

The Prime Minister will join events in regional centres such as Broken Hill and Port Lincoln, along with stops at Uluru, Melbourne, Adelaide, Perth, Hobart and Sydney.

Albanese confirmed on Sunday the government would not pursue future attempts at establishing the voice should the referendum fail to get enough support.

Deputy Liberal leader Sussan Ley said the country would still have negative outcomes following the referendum no matter the result.

“It’s a lose-lose whatever the result is on Saturday,” she told Sky News.

“It will be bad, divisive and unhappy for Australians the next day, so we do need to bring the country together.

“It is just so important that the day after we we come together as a country.”

Ley said she would not be happy if the No campaign won the referendum, despite saying she would be voting “no”.

The Australian Electoral Commission said more than 2.2 million people have already cast their ballot, while a further 1.9 million applied for a postal vote.

-AAP