Traditional owners from the Murray-Darling Basin have launched a court challenge to federal government approval of a plan to manage groundwater in the basin.
The NSW Murray-Darling Basin Fractured Rock Water Resource Plan, accredited last year, covers groundwater stored within cavities as well as alluvial sediments that lie on top of the fractured rock systems.
The Murray Darling Basin Authority acknowledged during the consideration process there were deficiencies in NSW's consultation with First Nations groups and people.
But the authority's chief executive Andrew McConville recommended approving the plan anyway in a letter to Environment and Water Minister Tanya Plibersek in November last year.
In the letter, Mr McConville said NSW had committed to work with the affected First Nations people over the following 12 months, and their objectives and outcomes would be incorporated into the water resource plan at a later date.
Ms Plibersek approved the plan in November.
A group of more than 20 Murray-Darling Basin First Nations people has launched a legal challenge against Ms Plibersek's decision saying they were not properly consulted, including about their social, cultural and spiritual values in relation to the water resources.
The Murray Lower Darling Rivers Indigenous Nations (MLDRIN) will argue the water resource plan does not comply with the law, and will ask the Federal Court to rule that the minister's accreditation of the plan is legally invalid.
Group chair Grant Rigney said they had been backed into a corner.
"We have repeatedly raised our reasonable concerns with Minister Plibersek. We have been entirely disregarded," he said.
Mr Rigney said the group wanted reform of the consultation process, improved provisions for First Nations water rights in the Water Act and the basin plan, including through the Restoring Our Rivers bill before parliament.
"We cannot wait for legislative reform," he said.
"This is urgent so we're taking this legal action now to ensure the law as it stands is upheld and our rights are respected."
Deputy chair and Tati Tati Millu Wudungi (Murray River man) Brendan Kennedy said proper consultation with the basin's traditional owners about the management of water resources was an inherent right.
"We hope not just to win this case, but to set a precedent that ensures that all Murray-Darling Basin water resource plans must be properly undertaken according to fair and reasonable standards of consultation," he said.
Acting on behalf of MLDRIN, Environmental Defenders Office special counsel Emily Long said traditional owners had been seeking water justice in the basin and getting nowhere.
"The Water Act contains only the barest of consultation requirements for First Nations and in this case MLDRIN argues that even those were not met," she said.
Ms Long said it was a requirement under the basin plan that traditional owners were consulted during the drafting process of water resource plans.
"This must be done properly to give First Nations a meaningful opportunity to contribute to water resource management and to care for their country," she said.
Mr Kennedy said the Murray-Darling was not just a river system, "it's our lifeblood, the source of our cultural economies, as well as an ancestral being".
"The result of 240 years of mismanagement and water dispossession is the ongoing suffering of our people," he said.
"Water is life for us, without it the injustice against our people continues."
A spokesperson for the Department of Climate Change, Energy, the Environment and Water said they could not comment because the matter was before the Federal Court.