The invasive water pest, the Mediterranean Fanworm, has been discovered for a second time in Tauranga Harbour about a month after it was first discovered.
Bay of Plenty Regional Council says several clubbed tunicate sea squirts were found, along with the fanworm, on a moored boat's hull in Pilot Bay.
Divers have been surveying the harbour for the Mediterranean fanworm since it was first discovered in late September and are close to completing the exercise.
The Mediterranean fanworm can grow in dense, thick mats that compete with native plants and animals for nutrients and space.
The council says the fanworms that have been found are immature and have not had the chance to breed.