Ports around the world are pledging their support for striking Ports of Auckland workers.
North American vice-president of the International Longshoremen and Warehouse Union, Ray Familathe, says international workers would consider boycotting ships that have been worked on by non-union labour in New Zealand.
"This is a key dispute on the radar of everyone right now... it's fundamentally deplorable," said Familathe.
"We're hoping things can be resolved locally."
Familathe's view is echoed by the president of the International Transport Workers Federation (ITWF), which has 4.5 million members.
"This is seen to be one of the biggest disputes in the international dock working industry in the last ten years. There's no doubt about it," said ITWF president Paddy Crumlin.
Union members at the Wellington and Tauranga ports are already refusing to work on ships loaded by non-union workers.
Bosses at Wellington's Centreport are seeking an injunction from the Employment Court after a small number of staff on Friday and Saturday refused to work on a ship recently arrived from Auckland.
Centreport chief executive Blair O' Keefe said the company is acting reasonably with the court order to maintain business.
"Staff are legally obliged to fulfil the conditions of their collective employment agreement and we hope that they will do that," he said.
The action follows an injunction in Tauranga where workers refused to unload a non-unionised Maersk ship.
O' Keefe said the dispute has not affected the company's other operations, with staff continuing to work on other vessels at the port.
"We have got other vessels awaiting loading but all other vessels are being served, and any vessels that are waiting it's predominantly on the back of the weather delays from the weekend, not related to anything else."
The hearing for the injunction is scheduled for tomorrow, but Centreport is still asking its workers to unload the ship today.