SYDNEY (Reuters) - Australia's Prime Minister Anthony Albanese said on Sunday he remained hopeful a referendum to recognise the country's Indigenous people in the constitution would succeed, even as the measure lags in opinion polls less than a week from the vote.

"I'm optimistic," Albanese told the Australian Broadcasting Corp (ABC) on Sunday morning, according to a transcript. "Whether it be Shepperton or Sydney or Brisbane, Melbourne, the places I've been, Hobart, Adelaide in the last week, have been extremely positive."

Albanese's centre-left Labor government backs the referendum, while the opposition Liberal-National conservatives urge a "No" vote on Oct. 14. Nationally, opponents lead the yes campaign by 53% to 38%, according to an opinion poll last week.

If the "Voice to Parliament" referendum is approved, it would constitutionally enshrine Indigenous people and set up an advisory body for their input on policies that affect them.

Most Indigenous people favour the change, but some say it is a distraction from achieving practical and positive outcomes and would not fully resolve the issues affecting them. The political opposition says the measure is divisive, would be ineffective and would slow government decision-making.

Marginalised by British colonial rulers and not mentioned in Australia's 122-year-old constitution, Indigenous Australians, who make up 3.8% of the population, face discrimination, shorter life expectancy, lower education outcomes and high incarceration rates.

As part of final efforts to buoy the yes side, Albanese on Saturday posted a photo to Social media platform X showing him casting his vote in Sydney in Australia's most populous state, New South Wales, where 4.2% of people identify as Indigenous.

Last month, thousands rallied in state capitals to support the yes campaign, which sees the measure as necessary to boost outcomes for the nation's Indigenous people.