Auckland Council is to carry out a census of homeless people, and is looking for volunteers to help.
The count will take place on 17 September and will take in the area from Wellsford to the Waiuku.
The council needs 750 volunteers to help it reach people living on the streets or in cars all over the region.
Mayor Phil Goff said the survey would focus on those living without shelter - like in cars or on the street.
"We are most worried about the people living in dangerous and life threatening conditions out on the street where they will die prematurely because of the cold, because of illness, maybe as a victim of crime."
Those living in temporary accommodation or bunking down with friends or family won't be part of the census itself, but Housing First will try to gauge the number by talking to community groups or social agencies.
Councilllor Penny Hulse says it will be challenging to cover such a huge geographical area but the information is crucial.
"People are very au fait with what happens in the city centre [but] it happens in Henderson, it happens in Ranui and we don't know because that's why the point-in-time count is so critical. Is anyone sleeping rough in Piha? This is our time to go out and have a look.
The council had housed about 420 people through its Housing First programme set up to get people into homes, then help them address the problems that led to their homelessness.
Housing First manager Fiona Hamilton said the September count would also include questions for homeless people, because the council needed more than just numbers.
Volunteers would work in groups of three, with a leader who had experience working in similar situations, such as a social worker, she said
"It's about also understanding the nature of this kind of homelessness - for example how long people have been homeless, how often have they been homeless, their health and wellbeing needs, whether they have access to an income," she said.
In 2016, the Auckland City Mission counted 177 people sleeping rough within a 3km radius of the Sky Tower.
A further 51 people who might otherwise have slept rough were located in temporary accommodation or in hospital.