The Maritime Union says it will take legal action over the "unlawful'' dismissal of nearly 300 workers.
Port of Auckland, the council-owned port company, faces an $11.5 million redundancy payout and weeks of disruption after a decision yesterday to make redundant almost 300 workers and replace them with contractors.
Following the decision, the union is seeking legal advice on whether port management's dismissal of workers during negotiations over an employment agreement is against the law.
"Ports of Auckland gave little consideration to our response to them on their contracting out proposal.
"We set out in detail all the problems with their proposal, but they have clearly just been going through the motions, and pushing ahead with their plan to take away job security for workers,'' said MUNZ national president Garry Parsloe.
The union had contacted Auckland councillors, asking that they intervene, said Mr Parsloe.
The union believed the Ports of Auckland would be unable to get its 235 members currently on strike back to work during a six-week notice period of redundancy.
Ports chairman Richard Pearson said he was looking forward to productivity improvements from greater flexibility resisted by the union, and said the port would be back to normal "10 weeks from now'', when employees of three new prospective stevedoring operations are up to speed.
But Mr Parsloe predicted great difficulties for the port company in recruiting new workers, despite internet advertising.
"They have kicked all of us out the door - a competent, qualified, trained-up workforce that [port company chief executive] Tony Gibson thinks are going to all run back in there and work for half the money,'' he said.
Mr Pearson believed the union would ultimately "realise they have made a huge mistake'' and tell its members that competitive stevedoring operations, such as seen in the Port of Tauranga, were inevitable and they should have a chance to work for them.
Yesterday, Labour leader David Shearer said the council should step up efforts to help to resolve "a hugely damaging dispute'' and Green co-leader Russel Norman described the port's actions as appalling.
They said Auckland Council and Mayor Len Brown had "sat on their hands'' for too long.
But Mr Brown said his hands were tied by legislation and it would be "absolutely inappropriate for me to jump into disputes or run the port out of the mayor's office''.
Council transport chairman Mike Lee said time would tell whether the port company's focus on "dealing to its workforce'', rather than negotiating better prices from shipping companies would significantly lower costs.
Ports workers will be holding a rally in Auckland at Britomart on Saturday.