The Sealord Group says its Nelson fish processing plant will remain open for at least the next three years now that a collective employment agreement has been reached workers.
Staff have ratified the deal, which includes a 24-hour roster and 10-hour shifts at peak times.
Workers will receive 8% over two years.
Sealord has previously said it would be cheaper to process fish at sea aboard factory trawlers, however, operations manager Shane Norton says the new agreement enables Sealord to commit to the plant.
The Service and Food Workers' Union says the 250 workers can feel relatively secure about their jobs following talks on the deal, which took nearly two years.