An animal rights group says the Ministry for Primary Industries (MPI) is "failing animals" by letting a factory farm get away with an "obvious breach" of animal welfare law.
On Thursday, Newshub revealed a Whangārei colony cage egg farm had dead and rotting chickens inside its cages.
Video footage, recorded covertly and provided to Newshub exclusively, showed birds so decayed they had been trampled flat by other chickens.
The footage also showed blood near eggs.
Despite the dead birds, MPI said on Friday it found no breaches of minimum standards.
SAFE campaigns manager Marianne Macdonald says MPI's findings are 'appalling".
"Farm workers may miss a dying or dead bird on one day, but if they had been effectively monitoring these hens, they would then see a dead body the next day, or even the next," she said in a statement.
"The rotting bodies shown in the footage prove that hens have been left for days, if not longer."
In 2016, similar video was captured at Heyden Farms in Waikato. A complaint was made to MPI, but it did not prosecute the farm.
"This is a case where MPI, again, seems to deliberately be turning a blind eye to factory farms breaking even the lowest minimum animal welfare standards. While MPI is missing in action, animals are suffering," said Macdonald.
MPI on Friday acknowledged the footage is disturbing.
"The footage of two dead birds is not something anybody wants to see," said director compliance Gary Orr.
"But MPI is cognisant this farm can be responsible for the care of up to 175,000 birds at a time."