Kiwi kids no better off than those in India's slums - author

"They are in houses that don't have heating, in caravans that don't have running water, and in families that simply don't have enough food of the right kind every day."

He said that even in India, poverty was relative. Most slum children went to school, health services were available and a high proportion of adults were working, albeit for low wages.

"It's on a long continuum, and in terms of that continuum some of our children overlap with the circumstances of children in developing countries in a way that I find quite shocking."

Children's Commissioner Dr Russell Wills, who appointed Dr Boston as co-chair of an expert group on child poverty two years ago, said New Zealand's living standards would drop in the future unless it invested more in the children -- mainly Maori and Pacific -- who now arrived at school at age 5 with the language of a 3-year-old.

"If we invest where it makes the biggest difference -- in preschool -- in the kind of evidence-based interventions that we know work, we can virtually guarantee that children will arrive at school at age 5 ready to learn," he said. "If we invest in those children, they will succeed."