Hillgrove Egg Farm. Photo: RNZ / Tess Brunton
Testing is continuing at other sheds at an Otago farm where bird flu has been confirmed.
It comes after the H7N6 virus spread to a second shed at Mainland Poultry's Hillgrove Egg Farm, meaning 80,000 chickens would need to be culled.
In a statement, Biosecurity New Zealand deputy director-general Stuart Anderson said further restrictions would be put in place if needed.
"However, at this stage, there have been no further reports of any avian influenza type symptoms showing in chickens in any other poultry farm."
The culling of the hens would start from Wednesday.
"This is expected to take two to three days, using existing industry standard practice of CO2 containerised gas, which farms regularly use to euthanise chickens. At present, there will be no major impact on egg supplies as New Zealand has about 3.9 million layer hens a year," Anderson said.
"Once the sheds have been depopulated, they will be thoroughly cleaned. It will be sometime before those sheds can be safely repopulated. We have Biosecurity New Zealand response staff on-site in Otago, and they are providing advice and guidance, including logistics and planning with depopulation and disposal of the birds."
Anderson told Checkpoint the delay in the culling to was due to more planning required with the second shed involved.
"We had the second property, a second shed that got confirmed last night. So, it's a bit of a bigger job compared to yesterday when we were preparing to just do the one."
After the chickens are killed, they will be taken to a landfill in Southland, he said.
"They will be removed and securely transported into landfill and securely buried, then a cleaning process commences of the shed that the birds have been in.
"It gets thoroughly cleaned and disinfected and washed down. It can be repopulated once we confirm the virus has been eliminated from the shed."
The chickens will be securely transported to the landfill in trucks by a private operator, he said.
"The birds are contained, and materials are all contained, securely in transport, which is some process that we've done previously when we've had these sorts of things to deal with."
Once they have got the all clear there is no virus detected on any property or in poultry in New Zealand, exports will be able to re-commence, he said.
"When we have that freedom status, exports can then resume and at that point, we can start talking to our trading partners about starting those exports up."
He said the first shed that had the virus had two halves, and at first, one half showed signs of illness.
"There are 18,000 birds the next half of the shed. By the time we heard the test results starting to come through over the weekend and there were probably around about 5000 or so birds that had actually died.
"Deaths started to occur during the course of the week and by the time we got to Sunday, when we had the confirmation that would have been the final number we had at that point."
Anderson was at the farm earlier and acknowledged it was a hard time for the farmer.
He said they took the right steps in notifying officials about their sick and dying birds.
"The farm has strong biosecurity standards. Three specialist veterinarians from the Ministry for Primary Industries (MPI) are on site.
"They have been carrying out further investigations and taking samples from birds in other sheds on the farm and conducting tracing work to six other poultry farms in the area that are linked to the affected property."
Anderson said any risk to the heath of humans remained low and there were no concerns for food safety or wildlife.
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