The trojan steals banking credentials and profiles of infected PCs.
Researchers from security firm Proofpoint said they had observed an increase in the number of emails which contained Ursnif targeting Australian users.
The email typically contains a Microsoft Word attachment and the content refers to it as an invoice that is due.
Another email posed as one from Tax Store Australia, a network of accounting firms and taxation professionals.
Proofpoint said many of these emails were sent by a financially motivated actor it referred to as TA543 aka Sagrid, who frequently abused legitimate email services like Sendgrid, Constant Contact, and Mailchimp to send malicious spam at scale.
TA543 has also frequently abused Microsoft SharePoint to host malware, although recent Microsoft security upgrades to SharePoint are limiting the ability of actors like TA543 to abuse the service.
While Ursnif appeared to be the malware of choice for targeting Australians over the last quarter, ransomware and other banking trojans also appeared in a number of campaigns.
Proofpoint said it had also observed broad, multi-regional attacks including the Locky ransomware and The Trick banking trojan affecting Australia while actors less frequently distributed other credential-stealing malware like CoreBot and Zloader in the region.
Two multi-faceted campaigns targeting Australia, among other regions attempted to install ZLoader, a Windows-targeting banking malware based on Zeus, and an Android banking malware variant in the same email.
Corebot was seen only in a few cases, Proofpoint said.