An urgent investigation is underway in Victoria after the sudden deaths of 10 horses on multiple properties.
Agriculture Victoria said the deaths of horses had taken place on three properties on the Mornington Peninsula, south-east Melbourne and south-west Victoria since July 4.
Agriculture Victoria chief veterinary officer Graeme Cooke said an investigation was underway to understand the possible cause of illness and death.
"The investigation is in the early stages," Dr Cooke said.
"It is not yet known what has caused these deaths and to date common links are not evident."
All horses are believed to have died quickly with short-term, non-specific signs of illness.
Reports on social media of other potentially-affected properties have prompted Agriculture Victoria to issue a warning to horse owners to alert authorities of sudden equine deaths.
"While we do not yet have any clear indication of the cause, early testing for some known diseases in horses has been negative," Dr Cooke said.
"Comprehensive testing for a range of diseases, and importantly, non-disease causes, is underway."
Dr Cooke said multiple horse deaths on a single property were uncommon.
"As this is early days, every report will help us understand the situation and assist our investigation into finding the cause," Dr Cooke said.
"We know this is a difficult time for horse owners, that's why we are working with veterinarians and a range of experts to find answers.
"Please do not share unconfirmed information online or on social media."
For more information, phone the emergency animal disease hotline on 1800 675 888
