Dogs registered for the first time after 1st July 2006 are required by law to be micro-chipped (livestock working farm dogs are exempt).
It is a good idea to microchip your dog anyway to ensure it is easily identified and quickly returned to you if lost.
Your veterinarian can microchip your dog for a small fee.
If any unregistered dog is impounded it must then be micro-chipped. Any registered dogs impounded more than once are also required to be micro-chipped.