Older adult abuse (OAA), defined as abuse, neglect, or mistreatment of persons aged 65 years or older, is a globally pervasive concern, with severe consequences for its victims. While internationally reported rates of OAA are in the range of 5–20% per annum, New Zealand lacks the necessary data to quantify the issue. However, with a growing aging population, an increase in the prevalence of OAA is predicted. We investigated the extent of OAA in New Zealand, utilizing the mandatory interRAI-HC (International Resident Assessment Instrument-home care assessment) dataset, which included 18,884 interviewees from the Southern District Health Board between 2013 and 2019. Findings confirmed our hypothesis that the interRAI assessment is neither sufficiently sensitive nor specific capturing only 3% from a population of increased frailty and thus at higher risk of abuse. We characterized OAA victims as relatively younger males, depressed, and with impaired decision-making capacity. If the interRAIs were to serve as a preliminary screening tool for OAA in New Zealand, it would be germane to implement changes to improve its detection rate. Further studies are urgently called for to test changes in the interRAI that will aid in identifying often missed cases of OAA better and thus offer protection to this vulnerable population.