The Farmers Union of Wales claims plans to publish details of individual single farm payments would expose members to illegal harassment and intimidation.
In evidence to the Welsh Assembly, the union has warned that “animal rights terrorists” could use the information to target livestock farms as they have research laboratories.
Also there was evidence that some farmers’ children had been bullied at school over the level of payments following the declaration of partial details in May 2006.
All 12 FUW county branches objected to the release of the addresses and postcodes of individuals and details of how much money they received.
“Publication would result in precisely the type of scenario that the Government intended to prevent when it revised the Data Protection Act in 1998,” said union president Gareth Vaughan.
“Many members question whether publication of what, in effect, amounts to personal data constitutes and infringement of both data protection and human rights legislation.”
There was extreme concern that such personal details could be release at a time when the public and businesses were being urged to shred any information criminals might use for identity fraud.