From the NParks website: The monthly Intertidal Guided Walk is temporarily suspended as marine debris washed ashore containing asbestos have been found at four isolated areas along the beaches in the lagoons on Big Sister’s Island.
As a safety precaution, we have cordoned off the affected beaches. We aim to complete the removal works by end June 2018 and will resume the guided walks thereafter. In the meantime, the affected beaches are closed to the public. We seek your understanding for the inconvenience caused.