Those houses will be for sale at prices ranging from $320,000 - below the current Mangere East median of $395,000 - up to $800,000 along the Manukau Harbour on the northern edge of the site.
The other 25 per cent of homes will be initially for rent or rent-to-buy.
Mr Sax said the project would draw on his past charitable work, such as a scheme that financed unemployed people to start small businesses, as well as on his property experience.
"We have learnt a lot from some of the not-for-profit things we have done. We have learnt from Kensington Park - that's an 830-residence development in Orewa in the middle to upper range," he said. "We have learnt a tremendous amount about how communities can be really dynamic and care for each other."
The four-year project will start in October, and 425 houses will be finished by next year.
Entrance roads will be built from Mahunga Drive on the west and from Walmsley Rd opposite Robertson Rd on the south.
Southpark bought the land from Trans-Tasman Properties and other investors in 2010. Although it is zoned industrial, the special housing area status is expected to enable a zoning change to residential use. Consents have yet to be granted.
Mr Sax said he was giving serious thought to including a school in the project and had reviewed Oasis academies, a chain of schools established in Britain by a Christian trust which also runs hostels for homeless people, social service "hubs" for low-income communities and development projects in the Third World.
"Oasis academies were among the top performing schools in Britain last year, but not all of them perform well," he said. "It's a matter of understanding why good ones perform well and why some don't.
"The good ones have a high level of community engagement and community support."
Mangere-Otahuhu Local Board chairwoman Lydia Sosene said she was impressed by the aim for "community wellness" but had not been consulted about a school.
John Sax
• Aged 59, married with two adult children and one grandson.
• Sole owner of Southpark property development company.
• Redeveloped former Affco and Hellaby meatworks sites.
• Built 830-home Kensington Park project at Orewa.
• Founded For the Sake of Our Children Trust 2008.
• Lives in historic Florence Court in Epsom.
• NBR Rich List values him at $100 million.