The Maritime Union has issued the Ports of Auckland with another strike notice - the sixth since an industrial dispute began in November last year.
The latest strike, for 24 hours, will begin at the end of January.
The notice was issued on Monday after mediation talks between the parties last week reached breaking point.
The groups have spent more than 100 hours in talks since the dispute began - and Ports of Auckland says it has had enough.
Chief executive Tony Gibson says the company still plans to make striking workers redundant and sent out requests last week for proposals from potential contractors.
Mr Gibson says Ports of Auckland will remain operational during the strike, as they have in previous ones.
The strike begins at 7am on 31 January and ends at 7am on 1 February.