"We need to know that there's not some kind of deal done that leaves the animals at risk," he said.
Animal rights activist Hans Kriek, director of SAFE, says the voyage will be tough on the cows and there's no guarantee they will be treated humanely in China.
"These animals will be slaughtered at the end of their productive life - and we don't even know how long that is," he said.
"They will be slaughtered, for instance, without stunning as is required in New Zealand.
The ministry says exporters have to meet rigorous standards around water, food, space, stockmen and veterinarians before export permits are issued. - NZN