'To have and to have not': the retention of DNA for criminal justice purposes in New Zealand

The retention of DNA from suspects and convicted offenders has potential societal benefits, including: identification and ruling out of potential suspects; matching to "cold cases"; and deterrence of individuals from crime. Developments in technology have led to the rapid expansion of state-controlled databanks, containing individuals' intrinsically personal information. New Zealand has had such a databank since the mid-1990s, but legislative reforms have expanded its remit considerably. This article considers the conceptual and operational issues relating to the retention of DNA in New Zealand and makes recommendations on the ambit and governance of the databank.