Any further commercial expansion of Auckland's port would be halted under legislation put forward by New Zealand First.
Winston Peters said the port company was acting "like some sort of warlord" in the face of strong public opposition.
NZ First has now lodged a Bill in the members' bill ballot. If it is drawn and eventually passed into law, it would limit any further expansion of the port.
"We have moved quickly with a Bill to freeze the size of the port and push any future growth to other ports," Mr Peters said.
"The Waitemata Harbour Protection Bill, if passed into law, will end the controversial wharf extension plans of the Ports of Auckland and ensure environmental and recreational protection for the harbour. In doing so we will be saving a recreational gem for Aucklanders."