| 15 Mar 2024

Health Warning lifted for Algal Bloom in Saltwater Creek/Otipua at SH1 Bridge

Health New Zealand | Te Whatu Ora has lifted its algal bloom health warning issued for Saltwater Creek/Otipua at SH1 Bridge. This was issued on 02 February 2024.

Recent cyanobacteria surveys of Saltwater Creek/Otipua at SH1 Bridgehas shown the amount of toxic algae (planktonic cyanobacteria) in the river has reduced and is now below levels that are of concern to public health.

Dr Matthew Reid, Medical Officer of Health for the National Public Health Service, says Environment Canterbury’s monitoring of Saltwater Creek/Otipua will continue to the end of this summer and then will resume next summer when there is increased likelihood of cyanobacteria growth.

The following warnings remain in place for the South Canterbury waterways due to ongoing algal blooms:

  • Pareora River/Pureora at SH1 Bridge
  • Hae Hae Te Moana River at Gorge
  • The entire Opihi River catchment
  • Temuka River at Manse Bridge
  • Temuka River at SH1 Bridge.

Facts about benthic cyanobacteria:

  • cyanobacteria occur naturally but can increase rapidly during warmer months
  • algal blooms are caused by a combination of nutrients in the water (such as nitrogen and phosphorus), and favourable weather conditions (e.g., increased temperature, calm days)
  • if the water is cloudy, discoloured, or has small globules suspended in it, avoid all contact
  • not all cyanobacterial blooms are visible to the naked eye and toxins can persist after the blooms disappear
  • cyanobacterial concentrations can change quickly with changing environmental conditions (e.g., wind). If a health warning is in place avoid contact with the water.

For further details visit: https://www.lawa.org.nz/explore-data/canterbury-region/

Or contact Te Mana Ora | Community and Public Health on (03) 364 1777:


For more information about Mahinga Kai:



For further information, contact:

Karen Berry
Public Health Communications Lead
National Public Health Service
Te Waipounamu
Health NZ
021 139 7442