A bare-knuckle fight is on between the New South Wales Irrigators Council and the head of South Australian Murray Irrigators Tim Whetstone - who is also a Liberal candidate for the next State election - over photographs Mr Whetstone took while on tour in south west NSW of a farm water meter, or dethridge wheel, which had been chocked and was not spinning.

Mr Whetstone claimed irrigators in NSW were stealing water by illegally tampering with water meters, and said he had heard from irrigation chiefs in NSW who allegedly said the practice of chocking meters had been considered a "national sport".

Support for the claim also came from an unlikely political ally, Labor Premier Mike Rann, who on Friday backed the alleged water thefts.

Mr Whetstone has since described water metering in NSW as "haphazard, inadequate and sometimes non-existent" and called for NSW Irrigators to prove there were no illegal diversions taking place anywhere in NSW before he backs away from his claims.

NSW Irrigators Council chief Andrew Gregson is furious and says categorically there is no stealing. He wants Mr Whetstone to apologise.

There is even a suggestion the council is preparing to run full pages advertisements in SA refuting the claims and attacking Mr Whetstone's credibility.

Council members agreed at their meeting on Thursday that unless Mr Whetstone takes his complaints to the proper authorities and can prove illegal meter tampering, he should retract his comments.

But Mr Whetstone is sticking to his guns. He told Rural Press that an irrigation trust boss said to him that water theft was happening and "widely regarded as a sport".

He said the fact irrigators did not have much allocation at the moment "was not the point".

"I've got photos of the sticks in the wheel and I've got acknowledgement that the culture of jamming the wheels is a sport," he said.

"When you get an admission from the CEO of an irrigation trust that this has happened, it rings alarm bells."

Mr Whetstone's claims are supported by SA Opposition River Murray spokesman Adrian Pederick, who was also on the tour.

He argues water theft is taking place throughout NSW, in particular in the Macquarie Marshes in the Central West of the state.