Auckland's striking port workers will be consulting their lawyers this afternoon.
It follows the threat by Ports of Auckland CEO Tony Gibson to replace 330 union employees with private contractors.
Maritime Union president Garry Parsloe says doing that may not be as easy as Mr Gibson thinks.
"There is a trade union movement in New Zealand that's not too happy with it and the world international shipping isn't very happy about all this," he told Newstalk ZB's Larry Williams.
Mr Parsloe says that's not a threat of industrial action - but a warning the union movement here and overseas will be looking at the Port.