Fonterra declined to reveal the names of the eight businesses due to commercial sensitivity.
A polluted pipe at its Hautapu plant in Waikato was responsible for the contamination, managing director Gary Romano said.
No report of diseases caused by these batches of products has been received, according a statement Fonterra sent to China Daily.
China has halted the import of all milk powder from the country, Reuters reported on Sunday, citing New Zealand's trade minister.
In addition, Australian baby formula maker Nutricia said it is recalling three batches of its Karicare infant formula from the New Zealand market. The product is also popular in China.
China's quarantine authorities said the three batches of products have not been imported to China through normal trade channels, but warned individuals to check the batch numbers if they have brought any such Karicare infant formula from New Zealand or bought such products through unauthorized channels online.
A search of "Karicare" on Taobao, China's leading e-commerce platform, on Sunday generated nearly 50,000 entries.
"The milk powder manufactured with contaminated raw materials might have been bought by customers through overseas purchasing but the three questionable batches have never been sold in our store," said a customer service executive from Nutricia, who declined to give her name.
Tests are not required for Clostridium botulinum under national regulations, said Cao Mingshi, deputy secretary-general of the Shanghai Dairy Association.
"The enterprise detected the problem by itself and took immediate recall measures, which is generally normal in the food sector," Cao said. "This is different from some defective products having led to major social harm and caused ailments to a large number of consumers."
More than 83 percent of China's imported milk powder came from New Zealand in the first half of this year, according to the General Administration of Customs, and experts predict the latest scare is unlikely to affect dairy imports from the country.
"Some consumers and experts predicted dairy exports from Europe would climb after dicyandiamide residue was found in milk produced in New Zealand in January, which didn't happen," Cao said.
Ou Hailin in Beijing contributed to this story.