Homeless people are dying about 36 years earlier than the general population, a Herald investigation has found.
Analysis of 130 coroners' and public reports showed that in the last seven years at least 45 homeless people died in New Zealand.
The figures come as part of a three-day investigation, Death on the Street, looking at the impact homelessness has on a person's life.
It's likely these figures are much higher as agencies which work with homeless people are reporting higher numbers.
In the coroners' reports, the youngest death was a man aged 25, the oldest was a 71-year-old woman and the average age was 45.6.
In comparison the World Bank puts life expectancy for New Zealanders at 81.6 years among the general population.
The Herald discovered getting conclusive statistics on homeless mortality was virtually impossible given there was no consistent classification for a homeless person across official reports and agencies.
Reports sourced from the coroners' office were of those classified as "no fixed abode" but not all were homeless and there were likely others not captured by the reports.
Those in the sector say there is no comprehensive data around those living and dying on the streets, or those whose death came when housed, but after a significant period of homelessness.
Meanwhile, the exact numbers of homeless people nationwide in 2018 are equally unclear, with the latest figures in line with the Government's definition of homelessness being five years old.
Main centres, such as Auckland, Christchurch and Wellington, have sporadically undertaken street counts in more recent years of those living in the cities' centres - but there is less data on the homeless living in the wider regions.
Efforts are being made to improve this. Housing Minister Phil Twyford has asked Statistics New Zealand to look into implementing a yearly nationwide street count and a biennial survey of those living in temporary, overcrowded and substandard housing.
"We have got to know the scale of the problem to have a decent chance of solving it."
Auckland mayor Phil Goff pledged in June to expand the SuperCity street count to the wider city region and to take responsibility for the city's "shameful" homelessness problem.
The first region-wide count is set to take place September 17.
The latest nation-wide figures based on 2013 Census data, compiled by University of Otago researcher Dr Kate Amore, show there are 4197 living rough on the streets or in a mobile dwelling.
An estimated 41,000-plus are said to fit the broader government definition that includes those living in insecure housing, vehicles, garages and overcrowded houses.
Meanwhile, a recent Auckland Council report estimated that based on the average rise between censuses in Auckland alone this figure could stand at 26,522 by 2021.
Experts say a life living rough, on the streets, has implications for a person's health and lifespan - even years after being housed.
Coroners' reports indicated common causes of death among the homeless were drugs, alcohol and street violence, alongside more preventable conditions such as asthma, bronchiectasis and pneumonia.
In one case in 2017, it was hypothermia, a condition typically caused by exposure to extremely cold weather.
Doctor Richard Davis is a general practitioner at the Calder Centre and treats a large proportion of the street community in central Auckland.
"There's no doubt [homelessness] causes death, you are more likely to die prematurely. It's very difficult to improve health while sleeping rough."
His records show the number of deaths among rough sleepers registered with the Auckland service has been growing in recent times.
At least 53 died in the past five years; in the first 10 months of 2017 records showed there were 11 that died, 14 in 2016 and 13 in 2015, 11 in 2014 and four in 2013.
From 2008 to 2012 there were two deaths each year, with the exception of 2011 when no deaths from the central city rough sleeping population were recorded.
"This seems to be a genuine increase, not that we are recording it better."
Davis said the average age of death among the rough sleepers in the inner city was 55.
"This is over 20 years less than New Zealanders as a whole ... which is pretty shocking."
Auckland City Missioner Chris Farrelly says the general population seem to be living longer, but those on the streets are not.
"In fact [their life expectancy] could be lowering somewhat due to some new factors around drugs and synthetics which are having a real disastrous consequence in terms of overall health."
The latest coroners' reports have not yet captured any deaths related to synthetics - a drug which in the last year has become a growing problem.
But word on the street was it would only be a matter of time, with unofficial reports of at least two in the last year who have died from the drug.
Across the general population police have linked at least 30 deaths to synthetic drugs since June last year, with an estimated 30 synthetics-related callouts a week.
Farrelly said health in the street community was complex and issues remained even years after someone was housed.
He said the serious trauma most had endured, combined with a life of deprivation, made for poor health outcomes long term.
"Life has gone on but the damage is done ... the complexity of sickness in people we are dealing with, you name it they have got it."
Chief executive of social service agency Lifewise Moira Lawler said the homeless were often invisible in society.
"There is an agency responsible for monitoring road deaths, or youth suicide. But who takes responsibility for the numbers of people that die on the streets?
"Really nobody does.
"Why are we concerned about cot deaths or traffic deaths, or even if you are ACC with people that die through injury? It's because we are trying to work out how to prevent that happening.
"And the fact that we don't even bother to count the deaths of people on the streets suggests that we don't yet have any leadership preventing it from happening.
"As to where you start? I don't know."
Housing Minister Phil Twyford said there were no plans in place at this stage to count morbidity and mortality of the homeless populations.
"We have been focused on getting the count under way."
But he said the number of deaths of homeless people in recent times was "distressing".
"That is something we should definitely look at as we get to know the homeless population better."
DEATH ON THE STREET
• At least 45 homeless people died in the past seven years
• The youngest was 25
• The oldest was 71
• Average age was 45.6
• Average life expectancy in New Zealand is 81.6
They die from:
• Violent assaults
• Respiratory diseases
• Cardiac diseases
Source: The Ministry of Justice
Today: The story of Rangi Carroll
Tomorrow: How they're dying
Saturday: Measuring homelessness