Climate change poses a growing threat to New Zealand’s water and health systems, with significant implications for national adaptation planning and water governance reforms. Rising global temperatures and more frequent extreme weather events are projected to increase the risk of waterborne enteric infections such as campylobacteriosis and cryptosporidiosis.

This review synthesizes evidence on how climate variability and seasonal shifts influence waterborne disease incidence in Aotearoa/New Zealand (NZ), identifies key transmission pathways, at-risk populations and infrastructure vulnerabilities, and suggests public health policy and climate adaptation strategies.

We conducted a scoping review following the PRISMA-ScR framework. Databases were searched for studies (published between January 2000 and July 2025), using Boolean combinations of climate-related terms (such as “temperature,” “precipitation,” and “season”) and waterborne pathogens (such as “ Campylobacter” , “ Cryptosporidium” , and “ Giardia” ) with “New Zealand.” Two reviewers independently screened records and extracted data on study design, climate metrics, health outcomes, and vulnerable groups. Supplementary searches using three AI-assisted tools were used to extend coverage and assess thematic areas.

Twenty-six publications met the inclusion criteria. Ambient temperature and extreme precipitation events were consistently associated with increased incidence of campylobacteriosis and cryptosporidiosis . Several flood-related contamination events highlighted vulnerabilities in small and rural water supplies. Children, older people, and Māori are likely to face elevated risks, though explicit analyses remain limited.

Clear associations exist between climate variability, seasonal shifts, and the incidence of waterborne diseases in NZ. Safeguarding public health will require integrated adaptation strategies, including source water protection, climate-resilient water and sanitation systems, equity-focused interventions, and embedding health into New Zealand’s climate and water governance frameworks.