The New Zealand Sheepbreeders' Association was officially founded on 28th May, 1894.

The decision to found such an Association came following several exploratory meetings held during the previous twelve months and was finally taken at the Agricultural Conference in Wellington by a full representation of the thirty-four Agricultural and Pastoral districts at the instigation of the Canterbury A & P Association.

A code of rules was compiled and it was agreed that to be eligible for entry in the Flock Book the uninterrupted use of purebred sires was necessary since the year 1880 and also it had to be verified that the flock was reputed to be purebred at that date.

A Council was appointed for each Island and on the recommendation of the several A & P Associations, local inspecting Committees for each district were appointed. These Committees consisted of persons who were well informed as to the purity of the flocks in their districts and they were responsible for inspecting the flocks before admission. Flock owners were required to furnish certificates in verification of the facts stated and flocks were admitted into the original publication of the Flock Book in 1895 on the advice and approval of the local Committees.

Volume 1 contained the histories of 291 flocks of the following breeds - Lincoln (82), English Leicester (48), Border Leicester (67), Romney Marsh (51), Wensleydale (1), Cheviot (2), Cotswold (2), Southdown (5), Shropshire Down (18), Hampshire Down (1) and Merino (14).

By 1898 registered flocks had increased to 395 and all rams used in registered flocks were subject to individual identification and single entry.

In January 1901, the Flock Book was opened for a short period for the admission of flocks which were eligible for entry in 1895 but which, from various causes, were not registered at that time. This was followed by a careful revision of the rules and the publication later that year of Volume 1. New Series which embraced the original volumes 1 and 11. The new rules provided for the publication annually, of a Flock Book showing the breeding returns of all flocks and these publications were made by the North Island and South Island Councils in alternate years. Provision was also made for the recording of pedigrees, transfers and export certificates. Ewes had to be individually identified either by label or tattoo and and the returns were required to show "Number of ewes to Ram" stating separately those retained from previous years and two tooths added. No sheep were eligible for transfer into a registered flock unless procured from a flock regressed with the Association or had been imported from a flock registered with the official Society in the country of their origin. Individual inspectors were appointed in each district who were required to report to the council on sheep for transfer.

The Association moved from strength to strength in the rapidly developing pastoral scene and by 1920 the number of flocks registered with the Association had increased to 604 representing 11 different breeds. The intervening period had seen the loss of the Wensleydale, Cheviot, Cotswold and Romney breeds (the latter having established its own Association in 1906), while the same period saw the introduction of the Suffolk, Ryeland, Halfbred and Corriedale breeds. In 1902 an appendix had been established for in-bred halfbred sheep to allow for the development of what was to become known as the Corriedale and 1911 annual returns for both Corriedale and Halfbred flocks were published for the first time, there being 1 Halfbred and 17 Corriedale flocks.

1906 saw the introduction of the Dorset Horn, Ryeland and Oxford Down breeds which were followed by the Suffolk in 1914. In 1916, 20 Corriedale flocks were raised to full status and 1924 the Corriedale Society was established and commenced publishing its own Flock Book, however, a number of these flocks remained with the New Zealand Sheepbreeders' Association until as late as 1948.

The Corriedale Sheep Society maintained its independence from 1924 onwards and in 1988 rejoined the Association, after an absence of sixty-four years.

Similarly the Southdown Society was established in 1926 and although the last 22 Southdown flocks did not transfer to the new Society until 1934 the loss of these breeds considerably reduced the total number of flocks administered by the Sheepbreeders' Association.

Volume 26 published in 1930 records 491 flocks which total had fallen away to 391 by the end of the next decade, however from 1940 onwards numbers picked up steadily as flocks increased and breeds such as Dorset Down, Hampshire, Poll Merino, Poll Dorset, and South Suffolk were either established, imported or were re-entered.

In 1940 a further special appendix was established for Southdown Suffolk sheep which after 13 years led to the original six appendix flocks being raised to full status as the South Suffolk breed. It is interesting to note that 24 years later the breed had 230 flocks mating over 16,000 ewes. The appendix was closed in 1968.

By 1960 flock numbers had risen to 826 although the Cheviots had transferred to their own society the previous year along with the last two Romney flocks. In 1971 the Ryelands returned to the Association and this was followed by the return of the Lincolns in 1975. In 1977 a special appendix was established for Border Leicester Corriedale sheep with the admission of 22 appendix flocks, the aim being to develop a new breed to be known as Borderdale. This section of the appendix was closed in1987.

In 1979 the South Hampshire Sheep Breeders' Association, which had been established in 1974, to develop a breed to be known as South Hampshire, was wound up and transferred its 32 flocks to the New Zealand Sheepbreeders' Association. This required the establishment of an appendix for Southdown-Hampshire sheep. A decline in the number of flocks has resulted in the South Hampshire breed being withdrawn from the Flock Book in 1992.

A further appendix was added in 1984 when the Drysdale Sheepbreeders' Association was wound up and fifteen flocks transferred to the New Zealand Sheepbreeders' Association. The history of this breed goes back to 1929 when Dr F W Dry began a series of breeding experiments aimed at increasing knowledge of the genetics of hairiness. Two years later he was given a ram lamb which had an extremely high proportion of halo hairs. By 1940, breeding studies using this ram and its descendants had established the existence of a genetic factor - the Nd gene - which caused the high abundance of hairs.

The Drysdale breed has been developed from Dr Dry's experimental flock with purebred Drysdales being sheep homozygous for the - Nd gene - (Nd/Nd).

In 1987 a group of breeders formed the New Zealand Lincworth Society and registered this breed of sheep, which they had been developing for several years. Based on the Coopworth and Lincoln breeds, the aim was to develop a sheep retaining the fertility, mothering ability and growth rates of the Coopworth and high fleece weight and longevity of the Lincoln. There must at all times be a fifty-fifty basis of Coopworth and Lincoln blood. In 1992, the Lincworth section was deleted from the Flock Book owing to insufficient flocks to maintain a Breed Society.

The importation from Scandinavia in 1986 by the Exotic Sheep Project (later to become Lamb XL) and the NZ Ministry of Agriculture and Fisheries of the Danish & Finnish Texel, Finnish Landrace, Gotland Pelt, Oxford Down and White Headed Marsh saw the commencement of a quarantined breeding programme resulted in the release of these breeds to the New Zealand farmer in November 1990.

In 1988, Lamb XL approached the Association for membership and the Danish Texel, Finnish Texel, Finnish Landrace, Gotland Pelt, Oxford Down, and White Headed Marsh are recorded in the 1990 Flock Book.

The sheep were released from quarantine late in 1990, and Breed Societies formed in 1991 for the Texel, Oxford Down and Finnsheep Breeds. In 1993, the Oxford Down Breed Society deleted 'Down' from their name.

The Polwarth Sheepbreeders' Association also joined the NZ Sheepbreeders' Association in 1990, after an absence of nineteen years.

In December 1992 eleven in-lamb ewes and four rams were imported from Sweden, and formed the base of the East Friesian breed in New Zealand.

In 1995 the first flock was registered by Silverstream East Friesians and 1996, several flocks were registered and this has continued, with 49 flocks being registered in the 1997 Flock Book.

In 1997 the South Dorset Sheepbreeders' Association was wound up and an Appendix section opened in the NZ Flock Book for South Dorset breeders who wished to breed through to Dorset Down status by crossing South Dorset ewes with Dorset Down rams. A purebred South Dorset section was also created.

In 199 the Stansborough Gotland breed was registered with the NewZealand Sheepbreeders' Association, and the breed has developed from the breeding of Gotland Pelts whilst selecting for specific traits.

In 2000 the Karakul, in 2001 the Dorper and in 2002 the SAMM Breeds were registered with the New Zealand Sheepbreeders' Association.

Due to the last remaining Gotland Pelt stud being withdrawn, the Gotland Pelt Breed was withdrawn from the Association in 2002.

In 2004 the TEFRom and Wiltshire Horn Breeds were registered with the New Zealand Sheepbreeders' Association.

In 2005 the only remaining Stansborough Gotland flock changed its breed name to Stansborough Grey due to its selection criteria concentrating on fine lustrous wool.

In 2007 the White Headed Marsh Breed changed its name to NZ Marsh and the Drysdale Breed was wound up.

In 2010 the Damara Breed Society was registered with the New Zealand Sheepbreeders' Association.

In 2010 the South Suffolk Breed Society changed its name to South Suffolk NZ, the Texel Breed Society changed its name to Texel New Zealand, the Suffolk Breed Society changed its name to Suffolk NZ, and the Border Breed Society changed its name to Borderdale NZ.