Marine health warnings
We monitor marine sites regularly over the summer to check for faecal indicator bacteria.
Sites that we monitor are given a long-term grade prior to each summer season for suitability for swimming . The grade is based on the last five years of sampling.
Sites that are not recommended for swimming, or any water-based recreation, because of their long-term grade are shown as red on the Land Air Water Aotearoa (LAWA) website and signage should be in place at the site.
This summer, the long-term grades at 13 bays in Whakaraupō Lyttelton Harbour and Akaroa Harbour are replaced with a new predictive water quality tool. This tool provides real-time information about the conditions. Learn more about the predictive water quality tool.
Temporary health warnings are issued when a site was graded as good to swim but there is now an increased risk of faecal contamination.
Faecal contamination poses a risk to health, it can cause gastrointestinal illnesses, respiratory diseases, and eye, ear, nose, throat and skin infections.
You can also help stop the spread of marine pests that pose a major threat to our region's beautiful coastal waters.
Temporary health warnings
Health Warning - Toxin-producing algal bloom in Port Levy / Koukourarata
Incident date: Friday 13 March 2026
Last updated: 3pm, Saturday 14 March 2026
Health New Zealand – Te Whatu Ora has issued a health warning after extremely high levels of paralytic shellfish toxins were found in routine samples taken from Port Levy / Koukourarata.
People should avoid the area and animals, particularly dogs, should not be allowed near the water until the health warning has been lifted. The algal bloom can produce toxins harmful to humans and animals and people should avoid contact with the water until further notice. The bloom appears to be limited to Port Levy / Koukourarata, but care should still be taken in nearby bays as toxins could travel to other areas.
New Zealand Food Safety (NZFS) has issued a public health warning advising the public not to collect or consume shellfish gathered from the northern side of Banks Peninsula. The warning extends from New Brighton to the northern side of Hickory Bay.
Rāhui issued for Koukourarata and Whakaraupō
Te Rūnaka o Koukourarata advises that, due to the presence of a toxin producing algal bloom currently affecting the Koukourarata / Port Levy Harbour, and the associated risk to public health, a rāhui has been placed on the taking of shellfish from the harbour.
The rāhui is effective from Saturday 14 March 2026 to Friday 20 March 2026, inclusive. A review of this rāhui will be undertaken once further water quality and toxin test results have been received.
Ngāti Wheke have also issued a rāhui on taking shellfish from Sumner beach, Scarborough, Taylors Mistake and all sites in Whakaraupō.
Find out more: Land, Air, Water Aotearoa (LAWA) - Can I Swim Here?
Advisory Note - Unsafe Recreational Water Quality at Whakaraupō Lyttelton Harbour bays
Incident date: Sunday 22 February 2026
Last updated: 1.42pm, Sunday 22 February 2026
Following the significant rain events last week and the subsequent wastewater overflows, water quality at Corsair Bay, Rāpaki Beach, Governors Bay Sandy Beach, Diamond Harbour and Purau Bay is considered unsuitable for swimming, other water-based activities, and shellfish gathering.
Te Hapū o Ngāti Wheke (Rāpaki) through the Rāpaki Tangata Tiaki have installed (as of 1700 hours on 21 February 2026) a seven (7) day rāhui on the taking of kai moana within Whakaraupō. Eating shellfish, fish and other kai moana from Whakaraupō should be avoided.
This rāhui also applies to Cass Bay Main Beach, Cass Bay Jetty, Charteris Bay and Church Bay.
Te Hapū o Ngāti Wheke are attempting to contact those with permits given over the last 24 hours and no further issuing of permits will occur during the seven-day rāhui or possibly beyond.
Find out more: Land, Air, Water Aotearoa (LAWA) - Can I Swim Here?
Advisory Note - Rainfall Affected Water Quality
Incident date: Thursday 18 February 2026
Last updated: 1.42pm, Sunday 22 February 2026
Don’t swim in estuaries, harbours, and beaches within 48 hours of significant rainfall!
Swimmers are urged to stay up to date on the quality of their favourite Canterbury estuaries, harbours and beaches to confirm they are safe to swim this summer.
When you’re heading for a swim, don’t forget to look out for the water quality information signs or visit ‘Can I Swim Here?’ section of the Land Water Aotearoa (LAWA) website at www.lawa.org.nz to view the latest information.
Swimmers should avoid getting in the water within 48 hours of significant rainfall as heavy rain flushes contaminants from urban and rural land into waterways, reducing the quality of water within a short period of time – even at sites that generally have good water quality. Check the water is clean and clear before taking a dip.
Find out more: Land, Air, Water Aotearoa (LAWA) - Can I Swim Here?