Southern Murray-Darling Basin irrigators say it'll take more than a $25 million federal funding upgrade of metering in the Northern Basin to rebuild confidence.
Announcing $25 million in federal funding for metering projects, federal Water Minister Keith Pitt said he hoped it would ensure transparency and trust, particularly around floodplain harvesting.
The Murray-Darling Basin Authority recently reported there needed to be greater consistency between the states over water metering accuracy and coverage.
Mr Pitt admitted there was a "real lack of confidence" in the current metering information.
"The money we are investing should give confidence to other users, that everyone is taking what they are owed and no-one is taking any more than that," Mr Pitt said.
Leading water researcher Maryanne Slattery said restoring confidence was about much more than improving metering.
"It's so hard to keep track of the spend (governments) have put into metering - they've been doing it since the National Water Initiative, back in 2004," Ms Slattery said.
The federal government had also provided a significant amount of money through national partnership agreements, in the past decade.
"This seems to be a case of the promise of more money, so it's no wonder no one trusts them," she said.
Resolving issues over floodplain harvesting was one way of restoring trust.
Ms Slattery said that was particularly evident when it came to NSW government claims the practice wasn't illegal, despite legal advice to the contrary.
"That is extraordinarily bad faith," Ms Slattery said.
"While they keep doing these things, and saying 'trust us", it tells us they are very misleading and liberal with the truth."
Wakool Rivers Association chair John Lolicato said inaccurate and out of date modelling of water flow and use meant no amount of money would rebuild trust.
"It's a matter of acknowledging there have been issues, to which the NSW government has turned a blind eye," Mr Lolicato said.
"You are not dealing with the real issue - there has been water taken out of there (the northern Basin), which has never been measured or monitored."
He said the proposed federal spending was similar to what the NSW government was doing with its five proposed Sustainable Diversion Limit Adjustment Mechanism projects.
SDLAM's allow the commonwealth Water Minister to adjust the Sustainable Diversion Limits, within defined parameters, on the advice of the Murray-Darling Basin Authority.
Sustainable diversion limits are how much water, on average, can be used in the Basin by towns, communities, industry and farmers.
"What NSW is doing now is using shiny beads and mirrors to drag people over the line," Mr Lolicato said.
"It's dividing our communities, in that one person might get a nice shiny mirror and the next one ends up wearing the consequences of it."
Southern Riverina Irrigators vice-chair Darcy Hare said everyone in the Southern Basin was compliant with metering.
"We know they are not complying (in the Northern Basin), we know they don't have licences," Mr Hare said.
"It's got nothing to do with confidence, because that's at zero."
He said non-compliant meters needed to be replaced, and real-time, in-stream telemetry installed, to determine flows.
"We need an acknowledgement, from governments, that they have allowed floodplain harvesting to far exceed the 1993-94 cap and an acknowledgement they are going to bring it down to 160 gigalitres of take in Queensland and 46GL in northern NSW," Mr Hare said.
That needed to be backed by publicly accessible information, proving the changes had occurred.
Third-generation Barham, NSW, irrigator and Speak Up deputy chair Lloyd Polkinghorne said the spending gave him no confidence.
"There's been lots of weird and wonderful changes up there, not just FPH - they can pump on lower rivers, they can pump with bigger equipment and all that contributes to reducing baseline flows," Mr Polkinghorne said.
He called for open and honest dialogue to increase transparency about Basin planning.
"Money means very little, to us, when we are watching our communities and environment being destroyed, with one off grants and things that are a band-aid."
The NSW Water Minister has been contacted, for comment.