The Government and the Southland regional council have so far spent nearly $400,000 trying to eradicate an invasive seaweed plant from Fiordland waters.
The pest plant Undaria, also called Asian kelp, was first found in Sunday Cove, Breaksea Sound, in 2010. It spreads easily by attaching itself to boat hulls or mooring ropes and can damage marine life.
Council biosecurity manager Richard Bowman says divers have so far hand picked 1887 pieces of Undaria from Sunday Cove.
Mr Bowman says while the weed has been uncontrolled in other parts of the country, the waters of Fiordland and the ecology there are too precious to do nothing.
He hopes Undaria will be fully eradicated from Fiordland within two years.