The Victorian Farmers Federation is warning against potential changes to water market rules that would expose commercially sensitive information to water speculators and personal details that put farmers' security at risk.
VFF president David Jochinke said any move to publish farmers' personal information would see them at risk to groups who oppose irrigated agriculture.
"A balance must be struck between privacy and transparency," he said.
"Making personal information public will expose farmers across the state to animal rights activists as well as environmental groups who oppose irrigated agriculture and want to examine irrigators' water use and individual farms' efficiency."
Mr Jochinke encouraged farmers to have their say and urged them to think deeply about the information they and their neighbours want exposed.
"The VFF is urging all farmers with an interest in water to complete the government's survey," he said.
"Farmers across Australia know all too well the dangers of publicising personal data in light of their recent exposure to animal rights activists through the Aussie Farms website.
"Farmers shouldn't have to risk their security in order to get water market transparency."
The Victorian Department of Environment, Land, Water and Planning (DELWP) has released a survey on what level of personal information irrigators are comfortable with being released around their water ownership, use and management practices.
Suggested information to be published includes home addresses, a map of where water is used and how much water is currently in their water accounts.
VFF water council chair Richard Anderson said farmers shouldn't have to risk their security in order to get water market transparency.
"The VFF supports changes to water market rules to expose large water traders who try to manipulate the market - in fact, we have put forward 20 recommendations to the Australian Competition and Consumer Commission (ACCC) to improve water market transparency," Mr Anderson said.
"However, we cannot support changes that would expose commercially sensitive information to water traders and speculators.
"Our bank account balances are considered as strictly private and the VFF considers that it is critical that farmers' water allocation account balances should be treated the same way."
Mr Anderson warned against changes that could lead to speculators and brokers having a greater ability to target irrigators.
"There is also a risk that irrigators will be targeted by water brokers and speculators who will be able to see individual account balances and potentially take advantage of more vulnerable farmers sitting on a zero balance when they need more water," he said.
Mr Anderson said only large water users should be forced disclose information on the water they use.
"The VFF has argued that like the stock exchange, when market participants own a certain percentage, they must disclose their shareholdings," he said.
"Irrigators need confidence that there is no excessive market power operating in the market and they need confidence the market is not being gamed by large traders."
Egg Farmer, Brian Ahmed said he is concerned about information being misused.
"I think farmers who are wanting total openness are not considering how private information can be used against them and their fellow farmers across the state," Mr Ahmed said.
"Our business is no stranger to attacks from animal activists.
"They will use any information they can and mislead the public to undermine farm businesses, just as they did creating the Aussie Farms map."
Farmers can access the survey at www.engage.vic.gov.au/water-market-transparency.
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