The Council of Trade Unions says labour shortages in the rural sector will continue unless pay and conditions and workers' prospects are improved.
The CTU accuses farmers and the wine industry of paying a pittance and shutting out New Zealand workers as a result.
Federated Farmers says that is not the case, and workers can earn an annual salary of about $35,000, comparable to many university graduates.
It says some New Zealand workers are seeking an unrealistic $50,000 a year plus accommodation.
But the CTU says that is a fair demand, considering the profits farmers are making.
Farmers and wine growers say the country relies on immigrant workers because a home grown workforce does not exist.
Wine Marlborough says a visa system is needed which would help it grow a long term workforce base with overseas workers.