The properties are near Bowen, in North Queensland.
The quarantine was imposed following a confirmed case of Hendra virus in a horse that died last week.
Biosecurity Queensland deputy chief veterinary officer Rick Symons said there were no longer any horses on the initial infected premise.
"The three quarantined properties are all neighbouring properties," he said.
"Biosecurity Queensland will continue to work with all affected horse and property owners and keep them up to date with the steps required to ensure the incident is contained.
"A thorough testing regime has been initiated with all possible contact horses to make certain this virus has not spread and these properties can be removed from quarantine and return to their normal activities.
"All horses appear to be healthy at this time."
Dr Symons said people in the Bowen area could get information on virus from static displays around town.
A mobile unit was to arrive in Bowen today with staff to provide further information.