The Reserve Bank says new security features on bank notes could require their design to be altered.
The central bank wants to incorporate the latest features to reduce the possibility of counterfeiting.
Head of communications Mike Hannah says the polymer notes in use are 12 years old and at the end of their life cycle but will not be updated until 2014.
Mr Hannah says the latest anti-counterfeiting technology is being investigated. A consultation process is underway and decisions on how the notes would be altered are yet to be made.