The Sea Lion Trust is warning the Government to act now so the mammals do not become a poster species for marine extinction.
The International Union for Conservation of Nature has changed the threat classification for the New Zealand Sea Lion from vulnerable to endangered.
Just 10,000 sea lions are thought to exist, and just a third are breeding females.
Trustee at the Sea Lion Trust Shaun McConkey does not think the change in threat ranking meant much.
"You just need to look at the responses for say Maui's dolphin where there's only about 55 of them left and there have been international calls for the Government to do something for them and there seems to have been relatively little response from the Government."
Mr McConkey hoped the Government would now do more science to figure out the biggest threats to the species.
The Government announced last year it was working on a threat management plan for the sea lions - which were ranked as critical by the Department of Conservation.