Labor says its candidate has held on to the Top End seat of Arafura in this weekend's by-election, with Manuel Brown set to represent the seat in Northern Territory parliament.
Mr Brown has secured 66 per cent of first preferences with more than half the votes counted, beating Country Liberal Party (CLP) rival Leslie Tungatalum.
Chief Minister Natasha Fyles declared the victory on social media after two hours of vote counting.
The result leaves the Labor government's majority unchanged with 14 out of 25 seats in parliament.
Only around 58 per cent of over 5,500 voters cast a ballot in the election, which Labor previously held by a 4 per cent margin.
Most votes were collected earlier this week as polling teams travelled across the electorate to major communities on the Tiwi Islands and in west Arnhem Land.
Neither party made specific election commitments to Arafura voters but promised to improve housing, health services and remote roads.
Labor sought to make the contest about the upcoming federal referendum on the Indigenous Voice to Parliament, contrasting its support for the Voice with the CLP's mixed positions.
The by-election was triggered by the sudden passing of Tiwi man and Labor member Mr Costa late last year.
Mr Brown, who also has Tiwi heritage, is based in the community of Maningrida, 500 kilometres east of Darwin.
NT Electoral Commissioner Ian Loganathan said the by-election turn-out was slightly higher than the 52.7 per cent recorded at the last general election in 2020.
He said the increase was encouraging, with by-elections normally drawing smaller numbers of voters than the general polls.
"But again, we're starting from a very low base," commissioner Ian Loganathan said.
"We would have hoped more people would have participated in this election."