The popular Matiu-Somes Island in Wellington Harbour will only be open for half days, due to a shortage of fresh water.
High temperatures and low rainfall this summer means there's less freshwater in the Hutt aquifer.
The Department of Conservation said from next week the island would only be open to the public from 8am until 1pm until further notice
DOC's Kapiti-Wellington operations manager Rob Stone said with limited freshwater available, the island could not cope with all the visitors.
He said if the dry weather continued, the island may need to be closed to the public entirely.