The Australian Communications and Media Authority has issued a warning about emails claiming to be reports of planned attacks on Sydney by ISIS.
The emails purport to be sent from News.com.au and have an attachment that contains malware. The emails claim that the attachment contains locations in the city that ISIS intends to attack.
A statement from ACMA said that it had received "numerous reports" about the emails since Sunday.
ACMA has advised recipients to immediately delete the emails.
A study conducted by the Ponemon Institute and sponsored by HP Enterprise Security found that malware was responsible for 9 per cent of Australian organisations' cyber crime related costs in 2014.
Overall, the 2014 Cost of Cyber Crime Study, which was published in October, found an 8.4 per cent year-on-year increase in the cost incurred by cyber crime for Australian organisations.