Timaru's port has confirmed it is losing all its container shipping work, threatening about 50 jobs.
PrimePort Timaru told staff on Tuesday morning that Maersk and Hamburg Sud have decided to stop calling there from 17 September this year.
The shipping companies have run a combined service which has supplied the South Canterbury port with almost all its container trade. After September, containers will be offloaded in Dunedin or Lyttelton and sent by rail.
PrimePort chief executive Jeremy Boys says the decision means the town will no longer have a container port. The company has about 85 permanent and casual staff, and many will be affected.
The South Island organiser of the Rail and Maritime Transport Union says staff had no idea before Tuesday morning that Maersk and Hamburg Sud were pulling out.
John Kerr says 90% of PrimePort's operations staff are involved in container handling and expects that more than 50 jobs will go. He says the decision is devastating for the workers and will have a massive impact on Timaru.
Mr Kerr told Checkpoint on Tuesday the country's ports are all fiercely competing with each another and shipping companies take advantage of that.
He says to stop the cycle of good business and no business at all, there needs to be a return to the central planning that existed before the harbour reform in the late 1980s.
"We've got this insane boom and bust in this competitive free-for-all. What we need here in a strategic industry like the ports is a little central planning. We used to have that before harbour reform ... and a country of four million people at the end of the world is what we need again."
Mr Kerr says what the shipping companies are doing is not commercial commonsense, but rapacious capitalism.