Opponents of planned Auckland wharf extensions have been given a High Court date to argue resource consents were granted to Ports of Auckland unlawfully.
Urban Auckland, which aims to protect the city's built environment and waterfront, is taking legal proceedings to stop the ports company from starting on construction next month.
The group's chairwoman Julie Stout said the society was testing the legality of the resource consents for the Bledisloe Wharf extensions, which were not notified to the public.
She said the hearing would be at the High Court in Auckland on 16 April.
The port company's plan to extend further into the Waitemata Harbour has sparked controversy, including a protest letter signed by dozens of prominent Aucklanders.
The proposal would see the two sides of Bledisloe Wharf extended by 98 metres, with a possible future reclamation of the land between them.
Auckland Council has asked Ports of Auckland to delay the extensions until a scoping study into the port company's development is completed.
The port company has said the extensions are urgently needed and, if they do not go ahead, some ships may need to be turned away.