Child abuse and neglect are consistently found at higher rates in families facing low income and income insecurity, and in contexts with lower public spending on children and families. However, child abuse and neglect, particularly as measured through engagement with child protective services, has deep intergenerational and institutional causes, casting doubt on the effectiveness of income transfers alone to reduce it. In 2018, Aotearoa New Zealand introduced a “Families Package” of policies, including a small, unconditional cash transfer to mothers with children under three years of age, which increased family income by 5\% on average. Using four years of national administrative child protective services and hospitalization data and difference-in-difference models, we find that the introduction of the Families Package was associated with a 19\% (OR: 0.81, CI: 0.80-0.81, p.value=0.003) reduction in overall referrals to family services in nonurgent cases of suspected maltreatment, without significant changes in urgent cases. For Māori, the indigenous people of New Zealand, and those for whom the child protective services had recorded notifications of concern for older (half) siblings, the reduction was 26\% (OR: 0.74, CI: 0.61-0.91, p.value=0.003). The Families Package likely also reduced neglect in single-mother families (OR 0.6, CI: 0.38 - 0.93, p.value=0.022). We find no statistically significant effects, however, on social worker findings of emotional or physical abuse, or for hospitalizations for traumatic brain injury.