NZ's homelessness the worst in OECD - by far

New Zealand has the worst homelessness in the OECD, new figures show.

YaleGlobal Online, a magazine published by the prestigious US university, says "more than 40,000 people live on the streets or in emergency housing or substandard shelters" - almost 1 percent of the entire population, citing OECD statistics.

Per capita it's well ahead of second-placed Czech Republic, and close to double the rate in Australia, which placed third.

"Homelessness is often considered embarrassing, a taboo subject, and governments tend to understate the problem," writes Joseph Chamie, former director of the United Nations Population Division.

While homelessness is usually higher in developing countries and failed states such as Somalia, South Sudan and Syria, Mr Chamie says there are still hundreds of thousands going without in the world's most stable and wealthiest countries.

Labour Party housing spokesperson Phil Twyford said homelessness was "National's legacy".

"Families living in motels, cars and garages; a record waiting list for state houses; Auckland City Mission forced to turn people away; homeless people dying in the street - these are the human costs of National's housing crisis, along with falling homeownership and skyrocketing rents," he said in a statement.

"It is simply shameful that National has not built the houses we need to give all our people a home. Labour first proposed KiwiBuild in 2012 - if National had adopted that plan five years ago, we would have built nearly 50,000 houses by now."

Figures released by Auckland Council earlier this week suggest there are around 24,000 homeless in Auckland alone.

Deputy Prime Minister Paula Bennett admitted on The AM Show on Friday the Government's response had been too slow.

"We had no idea how much it was going to cost," Ms Bennett said. "We had no idea it would ever be this big... In hindsight, you always wish you'd gone earlier".

It's costing the Government about $140,000 a day to house needy families in motels and other emergency accommodation.

"After nine years, even Paula Bennett now admits National got it wrong but, truth is, they won't change," says Mr Twyford.

Ms Bennett told The AM Show she couldn't give "actual numbers" on how the Government's emergency housing build was going, because she "didn't know we were going to talk about it this morning. I haven't looked at it for about a year."

After New Zealand, Czech Republic and Australia, the worst homelessness in the OECD per capita can be found in Canada, Germany, Sweden, UK and France.

The lowest rates are in Japan, Croatia, Portugal, Lithuania and Mexico.