NBR said Hart had recently put away his corporate chequebook and focused on deleveraging his packing empire.
Newly-revealed New Zealand citizen Peter Thiel is the second richest New Zealander with $3.7b worth of wealth.
The Todd family are third on the Rich List with $3.5b of wealth, mostly made in the energy sector.
The Chandler brothers both make the top 10 again this year. Richard Chandler, the elder of the two brothers is worth $2b and comes in at fourth on the list while his younger brother Christopher is ranked eighth with $1.4b.
According to the NBR the brothers inherited $10m between them and have turned that into billions by investing in Hong Kong real estate, Japanese banks, a South Korean oil conglomerate, and by getting involved in privatisation in Russia.
But Richard Chandler's fortunes have taken a hit in the past year, falling from $4.2b in 2016.
The Erceg family are number five on the list with $1.65b. Michael Erceg was thought to be worth $650m when he died in a helicopter crash in 2005.
But for the past three years his family have been embroiled in a legal dispute over two trusts worth $1.2b.
Property magnate Sir Michael Friedlander is number six on the list with $1.6b, while the Goodman family is seventh with $1.475b through its property investment and development business.
New Zealand born Greg Goodman has helped to return the family to billionaire status last year after he came close to losing his empire during the global financial crisis, NBR says.
Rich-list newcomer Soichiro Fukutake is ninth on the list with wealth of $1.4b. Fukutake is ranked in the 50 richest people in Japan according to Forbes but has called New Zealand home since 2009. Fukutake's wealth comes from the publicly listed Benesse Holdings - an education provider founded by his father in 1955.
Investment banker Stephen Jennings completes the top 10 with $1.1b. After a stint as a investment banker in Russia Jennings has now turned his sights on property development in Africa on a large scale.
Three rich-listers have dropped out of the top 10 this year. In 2016 Sir Michael Fay, Sir Douglas Myers and David Richwhite were ranked 9th equal with $900 million each.
Sir Douglas died in April this year. While Fay and Richwhite have seen their wealth grow to $920 million each it was not enough to get them into the top 10 this year.
NBR editor Duncan Bridgeman said the list showed New Zealand had become the land of opportunity for entrepreneurs and risk-takers.
Typically property had been "a good avenue for wealth creation", but among the newcomers a broad range of industries were represented, including manufacturing, agri-business, insurance, aviation and finance.
"The numbers don't matter so much, it's the stories behind the wealth we really get excited about.
"I think it's continued boom times for the rich, the rich get richer and the rich are having a really successful period at the moment."
