A Federal Court judge will decide if the National Offshore Petroleum Safety and Environmental Management Authority should have approved drilling in a massive gas project off the Tiwi Islands.
Tiwi Islander Dennis Tipakalippa launched legal action in June, saying the regulator should not have allowed Santos to drill eight wells in the Barossa gas field, 265 kilometres northwest of Darwin.
The Munupi elder said he was not consulted over the company's environmental plan and feared the project could damage his people's sea-country.
Santos, Australia's second-largest independent gas producer, said it had all necessary approvals following consultation with stakeholders.
Justice Mordecai Bromberg is due to hand down his decision in Melbourne on Wednesday afternoon.
During last month's week-long hearing, the court sat at Melville Island where Justice Bromberg heard from several witnesses in words, song and dance.
The court was told of the Munupi people's connection to the land and sea, and how they feared the Santos project would damage the environment and impact their way of life and spiritual wellbeing.
Santos argued the traditional owners from the Tiwi Islands were not relevant stakeholders in the Barossa project so they would not need to be consulted.
The $US3.6 billion ($A5.2b) offshore natural gas development is expected to create up to 600 jobs and pipe gas 280km to the Darwin LNG facility, with first production expected in 2025.
The company said the project, which it purchased from ConocoPhillips in 2020, is 43 per cent complete and on schedule.
The drilling that is the subject of the court case started in July but Santos last month agreed to halt most of its work ahead of Wednesday's ruling.
The company said it would not drill any new wells in the Barossa gas field and stop before it breaches the gas reservoir in its initial drilling.
