Biosecurity New Zealand and the Cruise Association say they are working together to reduce the number of cruise ships being sent for last-minute cleaning. Over the past month, four cruise ships have been denied entry or given only restricted access to New Zealand ports because of algal build-up or invasive species attached to their hulls. A joint meeting was held on Monday between Biosecurity NZ and the NZ Cruise Association to address the growing numbers of ships needing extra cleaning when they were already on their way to the country.