More than 260 people have signed up so far to sleep in their cars on the night of June 16 to show solidarity with homeless families.
"Park up for homes Mangere", a Facebook event created on Tuesday night by a group of 10 friends, aims to draw hundreds more to sleep in their cars in a Mangere carpark.
"It's to show that we care, as the so-called 'middle New Zealand', about those in our society who are doing it tough," said journalist Justin Latif, 34, who has lived in Mangere for six years with his wife Joanne, a graphic designer, and now their daughter Isobel, 2.
"We are not part of a group or anything," he said.
"I guess there are some loose connections through the fact that we are all Christians, but we all go to different churches, it's not like it's one church or anything.
"It's just a group of mates who work around Mangere and we all kind of have seen this for a few years."
Mr Latif drove around Mangere from about 10.30pm on Sunday night and found people sleeping in 12 cars at Mangere Town Centre, outside Countdown in Mangere East, behind the Manukau City Football Club, behind a hospice shop in Montgomerie Rd, under a tree further up that road, and in the airport shopping district.
Another organiser, Salvation Army policy analyst Annaliese Johnston, said the 6pm-to-6am park-up would be "family-friendly" with music, sausage sizzles and portaloos, and porridge for breakfast.
"We are inviting all the political parties to turn up and park up in their cars with their families," she said.
"We want it to spread into a nationwide campaign. We already have people expressing the need to do it in their own communities."
The group has aligned itself with the Child Poverty Action Group and will raise money for the Monte Cecilia Housing Trust.
By 6pm last night, 1800 people had been invited through Facebook and 266 said they were going.