A chicken farm in the New South Wales Hunter Valley is in lockdown due to a suspected case of avian influenza.
The Department of Primary Industries says the suspected virus is not the highly pathogenic H5N1 strain that has gained worldwide attention.
The ABC understands the property is near Hinton, with 45,000 birds potentially affected.
DPI chief veterinary officer Ian Roth says it does not look like the virus has spread.
"We've started tracing to see if it could have possibly spread, and so far that's looking quite good," he said.
"It looks like there's not a lot of potential movements for problems.
"But that's why we've got it locked down and our first response team activated."
Mr Roth says the farm's owners raised the alarm after a number of birds died earlier in the week.
"And it's kept going and there's been significant mortality, so the vet that looked at that was suspicious and hence submitted the samples for testing," he said.
The samples have been sent to the CSIRO's Australian Animal Health Laboratory.
The DPI is waiting on final confirmation but Mr Roth says it is suspected the virus is the H7 strain.
He says there is no risk to human health from this strain.
"No, certainly with the H7s the NSW Food Authority and NSW Health don't consider that from eggs or poultry products that there are human health concerns," he said.
Dr Roth says people who notice sick or dead birds should contact their local veterinarian or call the Emergency Animal Disease Watch Hotline on 1800 675 888.