The Australian Livestock Exporters Council said the breeder sheep deaths happened on Saturday, August 17, after the animals — which departed from Sydney on a plane — had been checked and deemed healthy.
The department of agriculture, as the regulator of live animal exports, is investigating.
"It is premature to comment on the incident or speculate as to possible cause at this time," a department spokesperson said.
The Dorper sheep were headed to Jakarta.
According to government data, 11 sheep have died while being exported by air between 2019 and 2023, with 132,499 sheep exported by plane during that period.
The council, LiveAir, the exporter and the air freight operator will work with the regulator as the investigation progresses.
The RSPCA has long campaigned against live exports by sea and says the industry is “unfixable”.
“We expect the exporter, and the government as the regulator, to be open and transparent with the Australian community about what happened, what went wrong, and what steps will be taken to prevent this happening with any more Australian sheep in the future,” a spokesperson for the RSPCA said.
Live sheep exports by sea will be banned from May 2028 after legislation passed the Senate in July, but air exports can continue.