The union for port workers is joining opposition to the government's plans for resuming live animal exports.
The trade was banned last year over welfare concerns and the 2020 sinking near Japan, of Gulf Livestock 1 that had sailed from Napier on its way to China. Forty-one men and nearly 6000 live cattle died.
The government has delayed the release of a public discussion document on the issue until next year but remains committed to reinstating the trade that was worth $374 million in 2022.
This time around, it is promising the highest standards of animal welfare and gold standard transport ships - but has not provided specifics.
The Maritime Union, which represents watersiders and stevedores who have in the past loaded freighters including the ill-fated Gulf Livestock 1, has voted to oppose their return.
Victor Billott from the Maritime Union, said in addition to animal welfare and cruelty concerns, live exports were not a good look for New Zealand.
"We just think New Zealand would benefit from being seen as a kind of modern and progressive exporter that doesn't carry out such bad practices that have grown to be unpopular."
Maritime union votes to oppose resumption of live animal exports
In the past the live animals trade was not a huge amount of work for waterfront workers.
"The jobs aren't really there, the money's going to a relatively small number of people and the downside really outweighs the upside."
The investigation of the capsize of the Gulf Livestock 1 had revealed the vessel's "poor conditions", Billot said.
The government was now promising the trade would resume to a gold standard for the ships being used, however, it had little credibility because in the past several vessels had been poor quality, he said.
They used flags of convenience which meant vessels could be registered to a country with low standards and no enforcement of any laws.
"We're kind of hamstrung in dealing with the conditions on those ships in terms of their seaworthiness and also the conditions crews have to put up with and sometimes the livestock."
Billot said he had no confidence in the government's assurances of top quality vessels being used for the live exports once it resumed.
If a disaster happened, it would emerge once again that New Zealand did not have adequate laws that governed shipping in this country "that really guarantee any kind of standards, let alone a gold standard on these vessels".
Health and safety concerns would be grounds for not working on a ship in New Zealand, however, employment law meant union members would usually have to abide by what the companies wanted.
That was partly why the union was speaking out against a law change.
"We just think it should stay like that and it solves a problem."