Scientists are holding a summit in Nelson this week to try to get some answers on how the sea slug, which has washed up on another Auckland beach, produces toxins.
Scientists blamed tetrodotoxin, a poison found in sea slugs, for the deaths of five dogs who'd been on Hauraki Gulf beaches.
Slugs have been found this week on Kohimarama Beach and, last month, along Narrow Neck Beach in Devonport.
The chief executive of Nelson's Cawthron Institute, Gillian Wratt, says no one knows how tetrodotoxin is produced.
She says scientists from a number of universities and regional bodies will meet in Nelson on Friday to try to get some answers.
The poison is also found in the Japanese delicacy, the puffer fish.