Animal rights groups are alarmed at the increasing number of animals being used for experiments.
Last year, 341,520 animals were experimented on - the highest number since records began in 1989.
The National Animal Ethics Advisory Committee's latest statistics show 38.5% more animals were used in testing in 2008 than in the previous year.
Mice, sheep, cattle and fish account for about 80.8% of the animals experimented on.
Hans Kriek, from the group Save Animals from Exploitation, says the rise is shocking and more work needs to be done to find alternatives to animal testing.
However, the National Animal Ethics Advisory Committee's chairperson, John Martin, says fluctuations in the numbers can largely be attributed to a three-year reporting cycle for long-term projects.
He says the increase possibly reflects more scientific work being conducted in New Zealand.