South Island dairy herd numbers grew to 2.1 million, with Canterbury the island's largest dairying region, recording 10% growth to 918,000.
Canterbury was followed by Southland, where numbers grew 19% to reach 589,000, according to the final results of the 2009 Agricultural Production Survey.
National dairy herd numbers reached a record high of 5.9 million at 30 June 2009, up 282,000 since 2008. The size of the North Island herd remained stable at 3.8 million.
Factors contributing to the South Island growth include continued dairy conversions, a smaller number of dairy cows and heifers going to the beef herd, more older cows remaining in milking herds, and the sourcing of dairy heifers from the North Island.
"In 2009, South Island dairy cattle numbers were almost seven times larger than 20 years ago when there were 312,000 dairy cattle," said agricultural statistics manager Gary Dunnet. "North Island numbers increased from 3.0 million to 3.8 million over the same period."
Between 2008 and 2009, sheep numbers fell to 32.4 million, deer numbers were down to 1.1 million, and beef numbers remained stable at 4.1 million.
The survey also showed continued growth in the planting of wine grapes and kiwifruit since 2007, the last time information on horticultural crops was collected.
The 2009 Agricultural Production Survey, conducted in partnership with the Ministry of Agriculture and Forestry, gathers data from farmers, horticulturists, and foresters.