NFU vice-president Gwyn Jones is among 21 dairy farmers charged with using an unlicensed labour provider to employ migrant farm workers.
Their case is due to be heard in court hearing at Swindon on 15 March.
The 21 farmers are charged with using the services of Marden Management, a Wiltshire-based employment agency.
It follows a lengthy investigation by the Gangmasters Licensing Authority (GLA) into the possible illegal employment of farm workers.
Marden Management supplied British and overseas agricultural workers to UK dairy farms – including about 60 Filipino migrant workers.
The GLA investigation found that Marden Management was not licensed as a labour provider.
It is a criminal offence to employ farm workers supplied by an unlicensed labour provider.
GLA officials passed their findings to the crown prosecutor within DEFRA, who has now decided to take legal action.
Marden Management director Chris Blakeney said his company had made an honest mistake. He believed Marden did not need a licence because it supplied qualified and experienced dairy workers, rather than unskilled labourers.
It is unclear at this stage whether Marden Management has been charged.
Nobody at the GLA was available for comment.
Mr Jones declined to comment.