Simon and Priscilla Cameron on Tuesday night won the Ermenegildo Zegna Vellus Aureum International Trophy in Sydney, beating entries from Australia and South Africa.
To qualify for the trophy, fleece has to be finer than 13.9 micron and have a soft quality.
The fleece came from a six-tooth wether, part of a 250-sheep ultra-fine flock which is housed overnight and let outside during the day.
In addition, the Camerons run a super-fine flock and 5000 commercial merino ewes. The bloodlines come from Russell and Jeanette Emmerson's Forest Range Station.
Mr Cameron said the award was for the New Zealand merino industry, as his success was due to the efforts of more people than him alone.
"It is a tremendous thrill and great for the New Zealand merino industry.''
The winning fleece weighed 1.47kg and, as part of the prize, the Cameron's receive its weight in gold, worth over $54,000, along with a sculpture.
Mr Cameron said in an interview that his first challenge was bringing 1.47kg of gold back to New Zealand.
"It's not something you put in the overhead locker.''
The Camerons scored 87.71 points to narrowly beat last year's winners, The Wool Factory, from Victoria in Australia, which scored 86.89 points with a 10.7 micron fleece.
The difference came down to the superior weight of the Cameron fleece.
North Canterbury farmers Robert and Debbie Leslie, from Glentara, in the Greta Valley, won the Ermenegildo Zegna VA International Challenge, for wool 14 micron to 17.9 micron. They entered a 14.5 micron fleece.
It was the first time New Zealand fleeces had won the two prestigious categories.
All entries have been bought by the Milan-based Zegna Group and will become quality menswear and accessories to be sold in the 525 Ermenegildo Zegna stores worldwide.