About natural hazards

This section gives background information about natural hazards in New Zealand and how it affects our health.

Natural hazards in New Zealand

New Zealand is susceptible to a range of natural hazards. Due to its geography and location, New Zealand is prone to an array of natural hazards such as earthquakes, volcanoes, erosion, landslides, and extreme weather events. It lies in a geologically unstable zone straddling the Pacific and Australian tectonic plates. New Zealand also lies in the path of the roaring forties weather systems, which means that we are buffeted by strong westerly weather patterns and occasional tropical cyclones from the north [1].

Flooding is the most common natural hazard in New Zealand and earthquakes and tsunamis are potentially the most damaging and disruptive [1].

In New Zealand, a natural hazard is defined in the Resource Management Act as:

“…any atmospheric or earth or water-related occurrence (including earthquake, tsunami, erosion, volcanic and geothermal activity, landslip, subsidence, sedimentation, wind, drought, fire, or flooding) the action of which adversely affects or may adversely affect human life, property, or other aspects of the environment.”

Climate change will likely increase the risk from natural hazards

Climate change is also likely to increase the frequency and intensity of extreme weather events, particularly flooding, storm surges, and drought. According to the latest climate projections for New Zealand [2], we are likely to experience:

  • higher temperatures
  • rising sea levels
  • more frequent extreme weather events
  • changes in rainfall and wind patterns
  • more drought
  • increased fire risk

The rise in population and land intensification also increases the potential severity and consequences of future natural hazard events.

See relevant information in the climate change section of the website.

How do natural hazards affect health?

Natural hazards can affect our health in several ways. It can affect us directly through trauma and injuries, and indirectly, through contaminated drinking-water supplies, particulates in the air, exposure to hazardous substances, displacement and disruption, or mental health [3].

Diseases and illness are more likely to spread when important infrastructure and services such as water, sewerage, and electricity are disrupted. For example:

  • Salmonellosis and campylobacteriosis can occur through eating contaminated foods
  • Communicable diseases such as influenza and measles can spread through poor emergency accommodation and overcrowding
  • Diseases spread by animals such as leptosporiosis can also become prevalent
  • Lack of medicines, particularly prescription medicines can increase the risk of illness such as diabetes, asthma or chronic obstructive pulmonary disease (COPD).

Who is more at risk?

People who are most at risk from natural hazards are usually our most vulnerable populations [4, 5]. These include:

  • infants and children
  • elderly
  • Māori
  • minority ethnicities
  • people living with a disability
  • single parent households
  • low socio-economic status groups

See relevant information about vulnerable populations here.

Case study – Indicators of social vulnerability to flooding in Porirua City

We are currently undertaking a two-year case study in Porirua City to develop indicators of social vulnerability to flooding. This study is funded by the Ministry for Business, Innovation and Employment (MBIE) via the Natural Hazards Research Platform.

Flooding is one of the most frequent and costly natural hazards in New Zealand and is expected to become more frequent and severe due to climate change.

Outputs of our project include:

  • an online mapping tool for exploring these social vulnerability indicators
  • integration of social vulnerability indicators into RiskScape
  • a report on how to develop social vulnerability indicators, and how the information can be used at a local government level to ensure that the effects of flooding on socially vulnerable communities can be reduced.
For more information

If you have any questions about this case study, email Helene Marsters at t.h.marsters@massey.ac.nz


1. MCDEM (2007). National Hazardscape Report. Officials’ Committee for Domestic and External Security Coordination Department of the Prime Minister and Cabinet, Wellington, New Zealand

2. NIWA (2016). 'Seven-station' series temperature data. National Institute of Water and Atmospheric Research. Accessed 21/08/2017 at https://www.niwa.co.nz/our-science/climate/information-and-resources/nz-temp-record/seven-station-series-temperature-data

3. Royal Society New Zealand (2017). Human health impacts of climate change for New Zealand – Evidence Summary. Accessed 19/07/2018 at https://royalsociety.org.nz/assets/documents/Report-Human-Health-Impacts-of-Climate-Change-for-New-Zealand-Oct-2017.pdf

4. DANIDA. 2000. Who Suffers? Identifying the Vulnerable Groups. Paper presented at the DANIDA Workshop Papers: Improving the Urban Environment and Reducing Poverty, Copenhagen, Denmark.

5. Hudson J, Hughes (2007). The role of marae and Maori communities in post-disaster recovery: a case study. GNS Science Report 2007/15, 51p

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