Hundreds of millions of dollars will soon land in state coffers to improve the health of the delicate Murray-Darling Basin.
The exact figure is due to be revealed in the coming weeks after the Albanese government revised the Murray-Darling Basin plan to deliver promised environmental flows over an extended period.
"It is in the realm of hundreds of millions of dollars," NSW Water Minister Rose Jackson told a budget estimates hearing on Wednesday.
"My understanding is that we've completed all the work that we need to conclude at our end and that we're just waiting on the Commonwealth to do the same."
A July report found the 12-year plan to restore Australia's largest and most complex river system to a sustainable level could not meet its June 2024 deadline.
South Australia has described part of the revised plan - a deal to return 450 gigalitres of water to the environment by 2027 - as the "bare minimum" to ensure the river's ecology can withstand the next drought.
The plan is backed by NSW but has faced fierce opposition from Victoria.
What portion of the 450GL target would fall at NSW's feet remained unclear, Ms Jackson said.
She reaffirmed her state would not be involved in the water buyback market, in which farmers are paid to reduce their water take, noting research showing "unstrategic" rounds of federal intervention had skewed the market and hurt communities.
Federal Environment Minister Tanya Plibersek has suggested the Commonwealth will re-enter the market again this year.
But Ms Jackson flagged the introduction of tighter rules governing private irrigators to make it clear who could take water when and in what volume.
It follows a Bloomberg report exposing a confidential agreement by a water provider to withhold more than a hundred billion litres of water from users at the height of NSW's last drought, in 2019.
"These private irrigation organisations ... play an important role," Ms Jackson said.
"But honestly, considering their scale and their market power, I don't think that the current level of regulatory oversight is necessarily adequate."
The community needed more clarity from a state minister who had been in the job for nearly a year, opposition water spokeswoman Steph Cooke said.
"The minister failed to provide communities and stakeholders with any confidence around the opaque deal they've done with the Commonwealth on the Murray-Darling Basin plan," she said.
"We still don't know what they've signed us up to and, alarmingly, the minister doesn't even seem to know the amount of water the Commonwealth is seeking from NSW."
Ms Cooke said the minister had admitted that nothing had been done to put in place the structural adjustment packages needed should buybacks eventuate.
