A duck carrying a strain of bird flu has been found on a property north-east of Perth.
The Department of Agriculture and Food says the duck was infected with a low-pathogenic avian influenza, which is much less serious than the bird flu which swept through Asia.
It says it poses no threat to human health.
The department's livestock bio-security director Michelle Rodan said once the virus was confirmed, about 100 ducks and chickens which had contact with the sick bird in backyard enclosures were destroyed as a precaution.
"That's really why we do have these protocols in place so the virus itself is not an issue as it is," she said.
"It's just the potential if it got into a commercial poultry population and of it potentially mutating."
The ducks and chickens had been moved to a second property where a further 24 birds were also destroyed.
The department is monitoring other birds in the area.
Owners of backyard ducks and chickens are being urged to shield their flocks from wild birds to prevent infection by avian flu.
Dr Rodan says the disease occurs naturally in wild birds.
"I guess this is just a reminder really to bird owners that they should follow good biosecurity and keep their pet birds and poultry separated from the wild bird situation," she said.
The department is reminding bird owners to keep yards and aviaries clean.
It also advises owners that if they come across sick or dead birds, to contact their local vet or call the Emergency Animal Disease Watch hotline on 1800 675 888.