Tauranga Maori are objecting to Port of Tauranga's plan to deepen the harbour to accommodate giant container ships, fearing the loss of traditional pipi beds.
The company intends to spend up to $70 million dredging 15 million cubic meters of sand from the harbour and dumping it at sea.
The chair of Te Runanganui o Tauranga Moana, Colin Bidois, says local iwi fear the harbour's kaimoana may eventually be lost through pollution.
He says they must weigh up the loss of traditional pipi beds against the economic benefits of the port becoming the first in the country able to handle the next generation of super sized ships.
Mr Bidois says taonga is being lost, little by little, over many years, and the effect of that gradual loss is eventually very significant.
Port of Tauranga spokesperson Tony Reynish says the company has offered to relocate the pipi beds using divers.