Scientists from ViaLactia, a biotechnology offshoot of giant dairy cooperative Fonterra, found a cow in 2001 which naturally produced low-fat milk.
They have since successfully bred calves from the cow they affectionately named Marge that also produce skim milk.
But Fonterra sustainable milk growth general manager Mark Leslie told the New Zealand Herald on Monday that it could take at least five years until there was a herd big enough to produce the milk commercially.
ViaLactia chief scientist Russell Snell said Marge was discovered during a routine screening of dairy cows. The low-fat gene has also emerged in some of her calves, opening the possibility of developing low-fat herds.
When we found her daughters had the gene, that was the eureka moment, but the true holy grail will be to produce a sire with the gene, Snell was reported saying in the Dominion Post newspaper.
Skim milk contains up to 0.5% fat compared to about 3.3% for ordinary homogenised milk.
Marge and her daughters are being kept in a secret location, where they produce milk with a fat content of about 1%.