Ruapehu Lahars
The predictions are that massive lahars will overflow from Ruapehu in the near future. In one of the more extreme fundamentalist decisions made by the Government, they decided not to did a trench to allow the lake to harmlessly drain after some religious nutters claimed it would hard the spiritual integrity of the mountain. Local authorities have rightfully complained about cultural concerns being given a higher priority than the risk to life
So instead of spending $200,000 to stop a problem developing they have spent far more on how to cope with the lahar flows when they do come.
Not often a Government is stupid enough to choose an option that both costs more, and delivers less benefits and is mroe risky, but hey well done team.