A child advocate says New Zealand is sitting on a Polynesian timebomb if it does nothing about Maori and Pacific poverty levels.

Lobby group Every Child Counts has commissioned a report which says the country is "developing a brown social underclass".

It says of the 200,000 New Zealand children living below the poverty line, more than half are Maori or Pacific.

A combination of high dependency on benefits, high rates of single parenthood and a concentration of workers in the manufacturing industries keeps families trapped in poverty, says the report released this morning.

New models and polices to address family violence, particularly that suffered by children in low-income communities are needed, it says.

Spokesman Hone Kaa, who is an Anglican priest, said the levels of children in poverty were unsustainable.

"The report confirms what I have witnessed during more than 50 years of ministry and advocacy on behalf of our whanau. Maori and Pasifika children do not share in the success and prosperity enjoyed by other populations of Aotearoa.

"There is no level playing field and our children are subjected, disproportionately, to the malaise that emerges out of poverty."

Dr Kaa went further than the report and said the underclass already existed.

"We are actually exacerbating it and the hidden danger is that doing nothing for the young increases the possibility that we will explode. We are actually sitting on a Polynesian timebomb."

The lobby group wants increased investment in children in their first 1000 days of life and supports coroner Wallace Bain's call for mandatory state monitoring of children until the age of 5.

Dr Bain made the call in his findings into the 2007 death of abused toddler Nia Glassie.

"I really don't care for adults who say 'that's prying too much into my personal business'. As far as I'm concerned I want to save a child," Dr Kaa said.

The report argues that new ways of measuring well-being need to be developed which take into account Polynesian world views. It is dubbed the "capabilities approach".

The report says current economic measures such as GDP are inadequate.

While that sounded convoluted, said Dr Kaa, in practice it was simple.

"We have used Maori cultural frameworks within systems before and Maori have done well. Look at the kura kaupapa [immersion schools] and wananga [tertiary institutions]."

Dr Kaa said it would be two to three years before it was known if the Government's Whanau Ora programme fits the bill.

On a benefit
* 25 per cent working-age Maori people
13 per cent working-age Pacific people

Low incomes
* When in employment the groups are paid around 14 per cent lower wages

200,000 New Zealand children live below poverty line
* 59,651 Maori
* 44,120 Pacific

Source: Getting it right for Aotearoa New Zealand's Maori and Pasifika children.