A new report has detailed shocking levels of physical violence and neglect towards millions of Pacific nation children, sparking calls for better-targeted Australian aid programs.

The “Unseen and Unsafe” report team investigated child-rearing practices in seven Pacific countries as well as Timor-Leste.

It found as many as four million children experience violence at home – a staggering 2.8 million in Papua New Guinea alone.

The horrific results of the abuse include serious physical injury, unwanted pregnancies, sexually transmitted infections, mental trauma and even death.

Plan International Australia chief executive Susanne Legena described the figures as overwhelming and heart-breaking.

“Because it’s showing that in a place where children deserve to be safe, to be healthy, to be loved … is the place where they are most often experiencing this kind of extreme level of violence,” she said.

“The drivers behind the violence are complex and they are inter-generational. It includes things like poverty, it’s not knowing any better, not having access to parenting programs that help you to understand why violence against children is not a good thing.

“It can be cultural practices but it can also just be no access to services or laws that help you protect children in their own context.”

Plan, World Vision, Save the Children and ChildFund researchers also uncovered a litany of disturbing statistics.

One in four adolescent girls experience physical violence and one in 10 experience sexual violence.

More than half of all sexual violence referred to medical clinics involves children in PNG, where almost one in three parents report beating children “over and over and as hard as they can”.

World Vision campaigner Mercy Jumo told SBS News the findings highlighted the need for better-targeted aid funding from Australia.

“Let’s get better value for money because if we build beautiful roads and we build beautiful schools but neglect to support the child that will use these roads and will be in classrooms to be the best in terms of their physical and mental health, then we are shooting ourselves in the foot,” she said.

“We need to start at the root cause of the problem because right now some of the programs are addressing the symptoms. It’s like having an ambulance at the edge of the cliff. We need to get in early.”

And according to Susanne Legena, better-targeted programs do work in reducing the level of violence.

“What we have found is that when there are interventions to explain why [violence] is not a good thing to do to children, parents of course don’t want to do that, and they change their behavior,” she said.

“But what we need is more investment in being able to reach more parents and more communities with that really useful information about the long term impacts of that kind of really physical violence against children.”

She said failing to tackle the scourge could have long-term impacts.

“If children experience high levels of violence and anxiety and trauma, that has implications for how they develop, how they grow, what they are able to learn, how they are able to participate, what kind of jobs they are able to have. All of these have impacts on the economy over time.”