The Maritime Union says facilitation has broken down with the Ports of Auckland because of its unreasonable demands on workers, and more industrial action is possible.
The two parties entered court-ordered facilitation to reach a collective agreement following months of strike action, lockouts and protests since contract negotiations with the company broke in September 2011.
Earlier this year the company announced plans to make about 300 union members redundant, but that was put on hold and a facilitator stepped in.
Union national president Gary Parsloe says at a stopwork meeting on Monday morning, members voted for the union executive to decide what to do next, with a range of options including taking strike action.
He says any decision to take more industrial action would be very seriously considered as the union is aware of the costs to its members and disruption to the city.
He told Checkpoint he was still hoping to reach an agreement in the facilitation process, but at the moment, it was not working because of the company's demands.
Mr Parsloe says Ports of Auckland has put out a document that outlines something the two parties have not yet agreed to.
A report from the facilitator was due Monday afternoon. Ports of Auckland says it will not comment until it is publicly released.