A horse has died from the Hendra virus in northern NSW, the first in the state in nearly two years.
Tests on a second horse, five cats and dogs on the property north-west of Macksville have returned a negative result for the virus.
It's the third horse to die from the disease in the country this year, the other two in the Mackay and Tablelands regions of Queensland in January and February.
Biosecurity NSW's Paul Freeman says the 12-year-old Anglo Arabian mare had no history of illness and died suddenly.
"The horse was discovered dead and they immediately sought veterinary assistance," he said.
"The NSW Public Health Unit has investigated all the people that have had some contact and they're happy that the level of contact was minimal."
He says cases of Hendra in northern NSW are unusual.
There are a number of known colonies of flying foxes in the Nambucca Valley and the property was under their flight path.
"But initial looking at it, you'd say it'd be low risk for flying foxes," said Mr Freeman
The horse was not vaccinated against the Hendra virus, but the second horse on the property has since received the first dose of the vaccine.
He says vaccination of horses against Hendra hasn't been taken up with the enthusiasm that was hoped for, and points to a number of reasons for this.
"For some people the cost has been off-putting. The other is that the product isn't fully registered," he said.
Some horse owners are calling on the government to cull the flying fox population, but Biosecurity NSW's Paul Freeman says flying foxes are a protected species and there's no plans by the State Government for any large scale culling of them.
There are now 65 confirmed horse deaths caused from the Hendra virus since 1994, and authorities believe there's strong evidence linking another 20 horse deaths to the disease.