Some 125 jobs could go in South Auckland as food and coffee maker Cerebos Gregg's works to close down its plant.
The site in East Tamaki is due to close on 19 December this year. Chief executive Terry Svenson says the Auckland plant is becoming too expensive and inefficient to continue operating.
Cerebos Gregg's says all affected staff will still be kept on until then and it will help them find new work.
However, the Service and Food Workers Union says there is little hope of new jobs in the company's $10 million expansion in Dunedin.
Spokesperson Chas Muir told Radio New Zealand's Checkpoint programme on Thursday news of the closure was hard for staff to hear. He said they are loyal workers who were left dumbstruck and in tears.
Mr Muir said no other local food factories are looking for workers, and it will be hard for the staff to find jobs in their own communities.