Unite is lobbying Labour and Liberal Democrat peers in the run-up to the House of Lords debating the future of the AWB on Wednesday (16 January).
The Government is set to abolish the AWB.
Unite national officer for agriculture Julia Long said: "Many peers share our sense of outrage, both at the government’s plan to decimate rural workers’ livelihoods, and at the underhand and dishonourable way in which it has been done.
"The AWB’s abolition will take £247 million out of the pockets of agricultural workers in the next ten years, according to the Department of Environment, Food and Rural Affairs’ (Defra) own figures.
"The beneficiaries from such a move are clear – the big agri-business bosses and the major supermarkets hell-bent on driving down workers’ wages to poverty levels."
Unite will be calling on peers to reject the government's amendment to the Enterprise and Regulatory Reform Bill, abolishing the AWB during the debate in committee and in the subsequent vote at report stage at the end of February/beginning of March.
Unite said that 60 per cent of responses to the government’s consultation were in favour of retention.