A horse in north Queensland has died from Hendra virus, the third from the rare condition in Queensland in the past week.

The horse died at Cannonvale on the weekend, and tests have revealed it was carrying the rare disease.

But Biosecurity Queensland said the death was not linked to an outbreak of Hendra virus at a Brisbane bayside veterinary clinic earlier this month.

One thoroughbred racehorse died from the virus and a second horse had to be put down at the Redlands Veterinary Clinic, in the worst outbreak of Hendra since it killed trainer Vic Rail and 14 horses in 1994.

Preliminary tests have cleared 37 other horses at the facility of Hendra virus.

Ron Glanville, Biosecurity Queensland's Chief Veterinary Officer, said the latest death was not a cause for concern.

"There are more than half a million horses in Queensland and although Hendra cases are still rare, some cases are expected periodically," Dr Glanville said.

"Fortunately, Hendra virus does not spread like equine influenza, and is very difficult to catch.

"The horse at Cannonvale has no connection to the vet practice in Brisbane, and all scientific evidence at the moment points to the timing being a coincidence."

The coverage of the Brisbane outbreak prompted the Cannonvale vet, north of Mackay, to alert Biosecurity Queensland of the death, Dr Glanville said.

The death is the fourth occasion since 1994 where there have been unrelated Hendra virus deaths in Queensland, he said.

"Every new case and new piece of information helps to increase our scientific understanding of this rare disease," Dr Glanville said.

The property at Cannonvale has been placed under quarantine while Biosecurity Queensland officers inspect the site.

AAP 2019 Published 15/07/08