Ports of Auckland management have been accused of refusing to meet its striking workers and attempting to discredit them with a misinformation campaign.
Business worth $100,000 a week to the port is set to end up at Tauranga and Napier after Fonterra said it would move shipments away from Auckland.
The dairy giant said months of industrial action were behind its decision.
Maritime Union president Garry Parsloe blamed the ongoing disruption on managers, who he accused of offering "cut and paste" employment deals.
"The quantity of the offers is not the point. The quality and the genuine nature of the negotiations are what matter. One hundred offers are pointless if they are one hundred offers of rubbish."
Meanwhile, Auckland Council's Citizens and Ratepayers ticket is urging councillors to publically back port management in the wage dispute.
Its leader Christine Fletcher told Radio New Zealand the consequences of a lingering strike could be catastrophic for Auckland.
She urged Mayor Len Brown to back the port board.
Ports of Auckland chief executive Tony Gibson said the port was beefing up resources to keep terminal operations open through the continued industrial action. Further strike action is planned for a 48-hour period, starting on January 9.
To date, the industrial action has cost the port $2.82 million in lost revenue, port spokeswoman Dee Radrakrishnan said.
The prospect of more business has given Port of Tauranga's share price a boost. The stock rallied by 15c yesterday to close at $10.10 - a record high.
Gibson said that with the union threatening further strike action, it was "inevitable" that customers would look for alternatives and contingencies.
"Shippers need certainty and reliable service," Gibson said.