The clear answer is that there is no rational reason for people to take out their money, but that if they do the banking sector will cope. Many people may withdraw a few hundred dollars beforehand for groceries, in case EFT POS or ATM machines have problems on 1 January. That additional demand can be easily met. We have also been asked what would happen if people attempt to withdraw all their savings, either because they fear that bank computer records might be lost or that large scale withdrawals by others could cause banks to collapse. Neither scenario makes any sense.
Banks have multiple back-up copies of all records in case of power failure or the like.
The Y2000 problem will not cause any loss of customer records. Bank failures also don't fit the facts. Banks fail when their bad debts are so great that their capital is lost or their liquidity runs short. Banks in New Zealand are robust, and even potential debt losses from Y2000 business failures would not be sufficient to threaten bank solvency. The Reserve Bank will ensure adequate liquidity, so large scale withdrawals of cash at worst might lead to temporary shortages of available cash, but would not threaten banks' viability.