Around 50 Timaru port workers are expected to lose their jobs today, and the union is blaming the Government.
PrimePort management will meet with staff to discuss redundancies and restructuring.
Last month two big shipping companies Maersk and Hamburg Sud announced they would not be using the port in the future.
Rail and Maritime Transport Union organiser John Kerr says Prime Minister John Key should take responsibility.
"It's okay having a nice smile, but the fact is the port strategy in this country is broken and needs to be fixed," says Mr Kerr.
"John needs to stop smiling, he needs to front up to these workers and come up with some answers."
RadioLIVE