Authorities in South Australia said on Wednesday that it is "very, very likely" that the H5 strain of bird flu is spreading locally after the state identified 11 more suspected cases, local media reported.
Of the cases, seven were found in the state's South East and four on Kangaroo Island, the Australian Broadcasting Corporation reported.
While officials are still waiting for final testing results, South Australia's Primary Industries Minister Clare Scriven said it was "extremely likely" to represent "localised distribution" of the virus.
The state government expects results from a Commonwealth Scientific and Industrial Research Organisation (CSIRO) testing lab on Wednesday or Thursday to verify whether the disease is spreading locally between wild birds.
"What we've seen around the world is we can't stop H5 bird flu, and there has of course in every other continent around the world been local transmission," Scriven said.
Authorities have temporarily closed Seal Bay to the public to help protect the local sea lion population.
Scriven said there has been no detections of H5 bird flu in commercial poultry across the state or the rest of the country.
South Australia's first confirmed case of H5 bird flu was in a giant petrel found on June 14.
