The representatives of remote communities in Central Australia pose after their council meeting near Uluru to vote ‘Yes’ to a voice to parliament. AFP

An Australian constitutional referendum on Indigenous recognition is on track to be defeated amid strong opposition from older voters and those living outside cities, according to a poll published on Wednesday.

Early voting on whether to recognise Indigenous Australians in the constitution and create a "Voice to Parliament" to give them an avenue to advise the government on matters affecting First Nations Australians began on Monday.

However, with less than two weeks to go before polls close on Oct. 14, those opposed to the proposal lead the yes camp by 53% to 38%, according to a YouGov poll of 1,563 voters published on Wednesday. Some 9% of those polled were undecided.

Opposition is strongest among those in rural areas or on the outskirts of cities, where almost two-thirds of voters disapprove of the amendment, the YouGov poll found.

More than two-thirds of those aged 65 and over were against the amendment, with no leading yes 68% to 24%, the poll also found.

"The data clearly shows the contest is much closer in inner metro areas - but the Yes campaign is still struggling to move the needle across the country," said YouGov director of polling and academic research Amir Daftari.

Support for the referendum, the first since voters rejected a 1999 proposal to become a republic, has ebbed over the past few months with respondents in a poll last week saying the vote distracted from issues like the cost of living and housing.

A separate poll published on Tuesday showed a slight uptick in support for the proposal, with 43% intending to vote yes, compared to 49% for no.

The referendum debate has divided opinions with supporters arguing the Voice will bring progress for Indigenous Australians, while some opponents say enshrining one group in the constitution would be divisive.

Others against the Voice have described it as tokenism and toothless.

Referendums are notoriously difficult to pass in Australia, with only eight referendums being approved since it became a country in 1901.

Constitutional change requires a majority of votes nationwide and in at least four of the six states.

Reuters