Changes to the Murray-Darling Basin Plan are no closer to kicking in, with the Greens refusing to back the federal government's new approach.
With water recovery targets lagging behind the initial June 2024 target, Labor wants to extend the deadline to return 450 gigalitres to the environment to December 2027.
That approach has been backed by all basin states except for Victoria, but the Greens say that amounts to "kicking the can down the road" and want a number of environmental protections factored in before they support it.
The bill has passed the lower house but will need the Greens' backing in the Senate to be implemented.
The Murray-Darling plan sets out how much water can be taken from the basin annually while also letting an environmentally sustainable amount be returned.
A Senate report by a government-dominated committee wants the plan passed, but does suggest a number of tweaks.
They include more transparency measures, eligibility requirements for assistance packages to communities affected by water buybacks and more recognition of First Nations' water interests.
Proposed voluntary buybacks, which let farmers sell water directly to the government, are a prominent feature of the plan to recover more water but have faced stinging criticism from the coalition due to their ability to affect prices.
The committee said those concerns were "overinflated" and weren't backed by evidence.
"There is now an urgent need to recover the agreed volumes of water for the environment," its report said.
"The committee notes evidence that voluntary buybacks have proven to be the most reliable and cost-effective and efficient form of water recovery, with water recovered via irrigation infrastructure costing Australian taxpayers at least 3.1 times more per megalitre."
To support the plan, the Greens have made a number of demands, including a guarantee that it be delivered in full and on time, and that a basin-wide audit be conducted to ensure the modelling underpinning it is scientifically sound.
"Extending deadlines for recovery will just kick the can down the road," the party's MPs wrote in the report.
"Heading into a dry summer, the health of the river will be further compromised by climate impacts."
The coalition is against buybacks and doesn't want the 450 gigalitres recovered from the productive water pool.
"We urge the government to look at complementary measures, rules-based approaches and off-farm measures to deliver the environmental objectives of the plan," the party's MPs wrote in the report.
"We believe the focus of the basin plan must be on delivering against the environmental outcomes, not merely volumes."
The Greens said they would continue working with the government on the plan.
