"People want cheaper accommodation. They can't afford the private rentals at $400, $500 or $600 a week," he said.
"People go through divorce, they go through separations. Some are evading the police, numerous things."
Robert Nahi, 60, was referred by the Auckland City Mission after a period of sleeping rough.
He pays $170 rent for an older caravan and has $85 left over out of his sickness benefit for food and other living costs.
"I get a food parcel from the Salvation Army," he said.
Residents in the park's 40 caravans and five single flats get free bread twice a week thanks to Robert Minhinnick of the Coalface Trust.
A Korean church provides occasional meals and other soup kitchens visit.
Mr Nahi came down from Northland to work in the old Westfield meatworks in 1986 and had other labouring jobs until a lung tumour and asthma forced him to stop work.
He has no heater, worries about cockroaches, and plans to go back up north.
"The money is too dear here," he said. "I've got a marae up north, I've got about 40 acres, I've got a bach on it."
Ewen Campbell, 64, said he had lived in caravans most of his life "because I couldn't afford to live anywhere". He sees himself as a "NZ-born refugee".
"I don't particularly like living in caravans but I've got used to it," he said.
He doesn't fancy his chances of getting a pensioner flat.
"Why should I crawl to them? They don't care about you, me or anyone else."
But Des Waller, 74, said he enjoyed living in his modern Chinese-built caravan, one of a batch which Mr Garthwaite is installing to replace all the older caravans.
The new vans cost $225 a week, but Mr Waller prefers them to either a pensioner flat or living with his daughter and her family, where he was staying until he moved into the caravan six months ago. He has two heaters, a TV, microwave and fridge/freezer.
"I like living in my own space," he said. "It's safe here because they've got the cameras."
