"This was a good day, as First Nations have been respected by the court system," says Grant Rigney, deputy chair of the Murray Lower Darling Rivers Indigenous Nations (MLDRIN).

MLDRIN, a confederation of more than 20 First Nations in the southern Murray–Darling Basin, filed a Federal Court challenge in 2023 to the Commonwealth's accreditation of NSW's Fractured Rock Water Resource Plan.

They argued the plan was approved without the consultation required by the Water Act and that then Environment Minister Tanya Plibersek signed it off in 2022 without reading it.

The Murray–Darling Basin Authority (MDBA) had recommended accreditation.

On Friday, Justice Angus Stewart declared the accreditation invalid and ordered it be reconsidered.

He found the minister had not read the plan; but also found the MDBA acted lawfully in making its recommendation.

The plan, the first from NSW to be approved under the Basin system, sets the rules for managing fractured-rock aquifers — groundwater held in rock fissures and cracks that is vital for communities, ecosystems and cultural practice.

MLDRIN chair Brendan Kennedy said the ruling laid bare a pattern of disregard for First Nations voices.

"Decision makers have treated First Nations peoples disrespectfully and sometimes unlawfully," Mr Kennedy said.

"Sadly, this has been an all-too-common experience since Colonisation began. It is another example of water dispossession that has been ongoing for generations."

The court also broke new ground in protecting cultural knowledge.

Justice Stewart ordered that information provided by First Nations remain confidential indefinitely, likening it to commercial-in-confidence.

"There is a very high public value placed in the maintenance of the confidentiality of such information," he wrote.

Mr Rigney said the judgment should force governments to listen.

"MLDRIN maintains the plan is not consistent with Basin Plan requirements," he said.

"We invite Environment Minister Murray Watt to meet with us directly to hear our concerns."

The Environmental Defenders Office, which represented MLDRIN, said the outcome underscored the urgency of reform.

"The law must embed the rights protected under the United Nations Declaration of the Rights of Indigenous People, including the right to free, prior and informed consent," said EDO special counsel Emily Long.

The decision is expected to influence future water plans in NSW and beyond, as well as the 2026 review of the Basin Plan and the 2027 review of the Water Act.