The Maritime Union says it will seek legal advice over whether Ports of Auckland can make union members redundant and re-hire them through new stevedoring contracting companies.
The parties failed to come to an agreement on a new collective contract at mediation on Thursday. The mediation followed a strike by about 300 Maritime Union workers, the fifth since November last year.
The port company is proposing to make the workers redundant and restructure operations on the docks.
Maritime Union president Garry Parsloe says it seems strange that its members would be made redundant - some of them on redundancy packages of up to $80,000 - only to be re-hired.
Mr Parsloe says he will seek a legal opinion about the plan.
"We just need to get some clarity around what can happen and what can't happen. It just seems a little bit of a nonsense if all those people are .... on redundancy packages - you're talking millions and millions of dollars, and then they say they'll pick them all back up again.
"If it was that simple, we'd be signing the document now. So somebody doesn't seem to understand the situation."
Mr Parsloe says no new strikes are planned, the union still wants to negotiate a collective contract with the port and is prepared to take part in more mediation talks.
However, Ports of Auckland chief executive Tony Gibson says the Maritime Union does not understand the need for urgency in order to prevent more financial loss.
Mr Gibson says Ports of Auckland can't afford to continue meeting to discuss options with the union. He says change is needed now, and the company will put out requests for proposals from contractors on Friday.
Council of Trade Union president Helen Kelly says the main factor holding up the dispute is the port company's desire to get rid of the union.
Ms Kelly says Ports of Auckland acknowledged in mediation that the union had put up a proposal which resolved their labour utilisation issues, but still indicated it wanted the union out of the port.