Just sneaking inside the northwest Hawke's Bay region boundary on SH2 (Napier-Taupo Road) are the Waipunga Falls - easily viewable from a carpark just off the main highway. Be sure to walk around the viewing spot to ensure you also see the neighbouring Waiarua Falls.
Note, the carpark access is located in the middle of a particularly fast stretch of the highway, so are best viewed when travelling from Taupo to Napier as vehicles can safely pull off to the left. Look for the 'Scenic Lookout' sign approximately 400m back from the carpark towards Taupo - an approximate 55km drive from Taupo.