"These costs are all preventable," he said.
Maori and Pasifika children were among the children most affected, and were missing out on goods and services, including adequate housing, nutrition, warm clothing, and healthcare.
"Our work identifies a range of potential solutions to improve child outcomes, including community-led development, geographic targeting of family support services, improving the health of women of childbearing age, raising the quality and accessibility of childcare and early childhood education, particularly for Maori, Pasifika and low income communities, investing early in children's lives, creating clear, achievable targets for child well-being outcomes and collecting data to measure progress, and coordinating home visits and centre-based services," Mr Edridge said.
The report has been welcomed by many organisations.
Dennis McKinlay, executive director at Unicef New Zealand, said New Zealand's spend on children should not be considered as a social cost but as an economic investment for the future of the country.
"New Zealand currently spends US$14,600 ($17,500) per child whilst, in comparison, Scandinavian countries spend US$50,000 per child under six. Other countries, like the Netherlands, spend less but have better outcomes. The stark reality is that poor outcomes for children are costing New Zealand $6 billion per year in areas such as health, welfare services, crime and justice."
Labour Party deputy leader Annette King said it was a "sobering" report.
"Experts have told us, time and time again, that waiting until a child is identified as being vulnerable before intervention is pointless. The evidence to support what we need to do is crystal clear, but is being ignored by this government."
Green Party Co-leader Metiria Turei said the report reinforced the need for a plan to bring 100,000 children out of poverty by 2014.
"270,000 New Zealand children live in poverty - that's one in four. These are not nameless, faceless kids; they are our kids, and they deserve better," Mrs Turei said.
The report detailed how poor early childhood experiences not only limited the opportunities of thousands of children, but also cost down the line in increased health, welfare, remedial education and justice spending, Mrs Turei said.
The Green Party's solutions to bring 100,000 children out of poverty would cost $360m per year, or less than 0.3 per cent of GDP, she said.
"Contrast this with the $6b cost of doing nothing identified in this report, and it's a no brainer."
Social Development Minister Paula Bennett said the report backed government plans in early childcare, work testing for beneficiaries and asking parents on various benefits to work part-time.
- NZPA
