A marine biosecurity group says an unwanted invasive organism has been found in Nelson waters during a routine survey.

Styela clava can potentially alter the marine environment by displacing native organisms, and may spoil mussel lines.

Russell Mincher, regional coordinator of The Top of the South Marine Biosecurity Partnership, confirmed the discovery of the invader at Dickson Basin in Port Nelson.

A further survey into the extent of the infestation is planned for early June, once dredging is completed in the area. Marine Invader Threatens Mussel Industry