The Crimes Amendment Bill (No 2) creates a new offence of failing to take reasonable steps to protect a child or vulnerable adult from the risk of death, grievous bodily harm or sexual assault, which comes with a maximum penalty of 10 years' imprisonment.
Parents or people aged over 18 could be found liable if they had frequent contact with the victim, including if they were a member of the same household or if they were a staff member at an institution where the victim lived.
The legislation was partly driven by cases such as the deaths of three-month-old twins Chris and Cru Kahui from severe head injuries in 2006, after which police struggled to get information from family members.
Justice Minister Simon Power said he was delighted a broad section of the Parliament supported the bill.
"New Zealand has a shameful history of child abuse, and this bill will make an example of adults who put their interests before those of vulnerable children around them,'' Mr Power said.
The law also doubles the maximum penalty for cruelty to a child from five years to 10 years' imprisonment, and extends the offence to include vulnerable adults.
The legal duty to those parents and caregivers who have a duty to provide the necessaries of life is extended to also take reasonable steps to protect a child or vulnerable adult.
Mr Power said the law would strengthen the ability of agencies to hold individuals to account for harming the most vulnerable in our community.
"It ensures that not only will the perpetrators of these acts be held accountable, but also will those members of households who witness those incidents and turn a blind eye to the abuse, or fail take to take measures to stop ongoing incidents,'' he said.
"But it's my hope that the biggest impact will be to help encourage those in day-to-day contact with endangered children to come forward if they know that serious abuse or neglect is taking place.''
The law changes also increase the penalty for possession of an offensive weapon, including knives, from two to three years in prison. The bill passed its third reading 109 votes to 11, with the Greens, Mana Party, and independent MP Chris Carter opposed. - Amelia Romanos
