Fishing company Sanford is planning to close its Christchurch-based mussel processing facility.
The company said it would try and redeploy as many of the 232 people who are employed at the factory at other plants.
Sanford's chief executive Volker Kuntzsch said it had been in contact with major employers in Christchurch in the hope of finding jobs for workers.
"I think at first they didn't really grasp the extent of this message but over time we repeated it, we made sure everybody understood.
"You could see the penny drop and it is obviously very shocking experience to realise this may be the end of my employment at these facilities."
Mr Kuntzch said Sanford would consult with employees and unions and a final decision would be made in just under two weeks.
Janet Hawken, who has worked for the company for 15 years, said the closure would have a huge effect on the workers, many of whom were their family's sole wage earner.
"It's not really a surprise, the writing was on the wall really, but we all hoped it didn't happen.
"It's the nature of our job, something had to happen, the company can't run on empty all the time."
Service and Food Workers spokesperson Chas Muir said many couples worked at the plant, so if it was closed some families would lose their entire income.
Mr Muir said it would not be easy for the process workers to get new jobs in the current Christchurch market which was focused on trades and the rebuild.
He said the company should not have been dependent on wild spat that could be affected by weather conditions.