Meat company Silver Fern Farms says its decision to shed almost 250 jobs from its Belfast plant in Christchurch ends its programme of cutbacks.
Two slaughter chains at the plant are to close down, but the plant will continue to process lambs.
In peak season, the plant employed about 450 workers.
Employees were told on Tuesday that it would not reopen the chains because of a decline in livestock supply. The chains are currently closed for the winter. A consultation process has begun, with a final decision will be made on 5 August.
Workers say they are resigned to the fact that more than half of them will soon be unemployed, adding that they had been expecting the move for years.
The company has closed or sold off several plants around the country in recent months to match processing capacity with supply.
Chief executive Keith Cooper says Silver Fern Farms will be able to redeploy about 70 of the affected workers in the lamb-cutting operation, as well as its venison-processing plant at Islington.
Mr Cooper says South Island sheep and lamb numbers are expected to drop by more than 2 million next year.