Reduction involves identifying and analysing risks to life and property from hazards, taking steps to eliminate those risks if practicable, and, if not, reducing the magnitude of their impact and the likelihood of their occurrence to an acceptable level.

Most hazard events occur at the local or regional scale. Even large events will consist of many small incidents that together give the event its scale. Hence, New Zealand’s hazard and risk management and CDEM planning frameworks place a strong emphasis on local initiatives for risk reduction. Individuals, communities, and local government are best placed to decide on the management options suited to them, for example through land-use planning and building control activities.

The principles underlying reduction are to:

  1. Achieve acceptable levels of risk through sustainable and practicable reduction measures to provide the best long-term solutions
  2. Reduce the risks to communities from hazards, including a combination of the following measures:
    • - Modifying factors that affect the likelihood of an emergency where practicable to do so
    • - Modifying factors that affect exposure and vulnerability to consequences before, during, and after an emergency
    • - Minimising consequences through rapid and effective interventions during and after an emergency
  3. Recognise that every person, community, organisation, and agency has a role to play in reduction
  4. Facilitate a shared understanding of who benefits from, and pays for, risk exposure for the purpose of improving decision making throughout society in determining acceptable levels of risk
  5. Review reduction policies and programmes regularly to reflect changes in community goals and the relevant risks and vulnerability factors
  6. Take a precautionary approach to managing hazards and risks where there is
    • - Scientific or technical uncertainty about a hazard or risk
    • - Potential for cumulative or cascading risks to arise.