The Government has agreed to allow undaria seaweed to be farmed commercially on coasts where it is out of control.
Undaria (Japanese kelp) is cultivated for food and medical uses in Asia, but is on New Zealand's unwanted list because it displaces native ocean plant life.
It was accidently introduced to New Zealand waters in the 1980s and is found on much of the east coast.
It is spreading to the west coast and was recently found for the first time in Fiordland.
After years of lobbying, the aquaculture industry has convinced the Government to allow commercial farming and harvesting of undaria in areas where it's widely established.
Biosecurity New Zealand says specific areas for farming will be decided by a panel.