Tens of thousands of trans-Tasman citizens could cast ballots in two polls on the same day after Anthony Albanese announced the date for the voice referendum.

The Australian prime minister's choice of October 14 means the referendum will be held on the same day as New Zealand's general election.

New Zealand got in first with its date, with Dame Jacinda Ardern declaring October 14 as election day in her final act before announcing her shock resignation in January.

Under a convention started by Sir John Key, NZ prime ministers tend to name their poll dates at the start of an election year to allow for easier planning.

Mr Albanese confirmed the Australian referendum date on Wednesday.

The place of Indigenous people in decision-making will also flavour NZ's election, with "co-governance" a major bugbear of opposition parties.

Centre-right opposition National and right-wing ACT have campaigned for months against guaranteed representation for Maori in the management of natural assets.

Voting in the voice referendum will be compulsory for enrolled Australians living in Australia, with those abroad able to choose whether they cast a ballot.

NZ uses optional voting at its elections, with tens of thousands of Kiwis living in Australia expected to cast overseas ballots.