Anti-virus vendor Trend Micro says of those, about 75 are Australian businesses which have been infected in the last 24 hours.
Melbourne companies appear to be bearing the brunt of the worm.
-It's starting to spread quite quickly," Trend Micro's Ian Bigwood told ZDNet.
-The way it's disguising itself is fooling a few people," he added.
Bigwood anticipates variants of the virus will come through in the next week.
Symantec claims there are now over 2500 reports of the virus worldwide, with only 200 reported at the end of last week.
SirCam sends a random file from the infected computer's hard drive, potentially sending confidential business data or embarrassing personal information along with the virus. The subject line matches the name of the file being sent.
