Prime Minister John Key is on the verge of falling off the National Business Review's Rich List for 2012, with a reported $5 million drop in his personal wealth over the last year.

Key's estimated $50m fortune ranks him last place on the list, at 157, and just pushes him over the threshold for inclusion.

That figure is the same as when he first became a Rich Lister in 2008, although last year he rejected the accuracy of the annual report as “made up by a bunch of journalists”.

At the other end of the spectrum, the wealthiest person atop the Rich List - for the first time ever - is not a New Zealander.

A sprinkling of international investors added this year has swollen the ranks of the billionaire's club from six to nine, but also pushed the country's wealthiest down the ladder.

Six-billion-dollar Auckland business tycoon Graeme Hart has been usurped by Russian steel magnate Alexander Abramov, valued at $7b. Abramov is building a $40 million luxury waterfront home in the Bay of Islands.

The five new foreign investors have injected $13.4b into the list, skyrocketing the combined total value up to $57.7b from $45.2b in 2011.

But the 152 locally grown moneybags actually had a slight dip in collective wealth, down 2 per cent to $44.3b.

Waikato-born investment banker Richard Chandler ($5b) added another billion over the last 12 months to snap at Hart's heels in third place.

The Todd family ($2.7b) and Chandler's brother Christopher ($1.5b) maintained their fortunes but slipped down the list to fifth and sixth place.

NBR said the international additions aimed to reflect the globalisation of wealth, with most investing enough or owning sufficient assets to earn residency rights.

The Waikato's adopted aristocrat Dowager Duchess Henrietta Bedford ($1b) adds some blue blood to the list, with extensive property interests throughout the country.

NBR uses valuations of listed shares, sales of private companies and other valuation techniques to estimate the wealth of those ranked.

- © Fairfax NZ News