Maritime Union members at the Ports of Auckland are stepping up industrial action.
They voted on Tuesday morning to take more action from 15 - 22 February.
National union president Garry Parsloe says he will issue the strike notice to the port on Tuesday afternoon.
The notice is the seventh issued by the union since the dispute began in November.
The union says the latest will not be a continuous strike, but will involve members refusing to work some containers. It says the aim is to get the company to negotiate.
The company is not commenting until it receives the notice.
