Ports of Auckland workers are picketing outside the company's container terminal on Auckland's waterfront on Friday.
The company is out of action for four days during a dispute with the Maritime Union of New Zealand over the terms of a new collective agreement.
The industrial action began at 10.30pm on Thursday and is the first of two 24-hour strikes over the next four days, coupled with a two-day lockout on Saturday and Sunday.
It involves more than 300 members from the Maritime Union. Vice-president Carl Findlay says the strike was a last resort, but necessary.
A spokesperson for Ports of Auckland, Catherine Etheredge, says it is disappointing that the situation has come to this.
The company is urging the union to withdraw its strike notice so mediation can continue, she says.
