Rich-listers gave the New Zealand First Foundation $100,000 in just one week.
But the donations have stayed secret until now because the individual payments fell below the level where donors' names have to be published.
The Spencers, one of New Zealand's richest families, donated $50,000 to the foundation in July of 2017 - an election year - using a law firm to make the payments in four separate amounts.
The week before, Andrew Bagnall, and entities connected with the racing car driver turned businessman, also donated $50,000 to the foundation - again in four separate payments.
Electoral law specialist Andrew Geddis says these donations show the level at which donations have to be made public - is set much too high.
Guyon Espiner and Kate Newton from RNZ's In Depth team have been reporting on the New Zealand First Foundation. Kate joins Lisa Owen with the details.