People are warned to look out for toxic sea slugs on all beaches across the Auckland region, after a sea slug was found on the shores of the Manukau Harbour.

One sea slug was collected from Cornwallis Beach this week, and is assumed to be toxic. The sea slug will be tested for the presence of tetrodotoxin (TTX) - as found in sea slugs washed up on Auckland's North Shore beaches. Auckland Regional Council (ARC) and Waitakere City Council staff searched the beach yesterday and found no evidence of other sea slugs.

"There is no doubt these slugs are very toxic to dogs, and potentially toxic to humans as well," says ARC group manager monitoring and research Grant Barnes. "Children and pets should be very closely supervised on all Auckland beaches."

Mr Barnes says recent surveys continue to show Narrow Neck and Cheltenham beaches as sea slug "hot spots", with divers finding high numbers immediately offshore. Lower numbers of slugs were also found on other parts of the coastline throughout the North Shore and the Hauraki Gulf.

Research into the toxicity and distribution of the sea slugs continues. The ARC will continue coordinating the efforts of the various agencies involved in the response.