A statement from the ABF said the security update in question, issued on 8 October, had caused issues for many users worldwide.
The ABF did not offer any reason as to why its ICS is still customised to work only with Internet Explorer, a browser that even Microsoft has been asking users to give up.
Instructions on the ABF site say it is not possible to use the ICS with any system other than Windows, and any browser other than Internet Explorer.
And it adds: "Note for Apple users: It is not possible to connect natively to the ICS using OS X. A workaround for OS X users who wish to access the Customs Interactive is to use Microsoft’s Virtual PC for Mac. This product emulates Windows XP on a Macintosh desk or laptop, allowing OS X users to access the ICS."
The ABF statement added: "Our technical teams are working with Microsoft at the highest priority to understand and resolve the root cause of the issue and to develop an appropriate solution.
"A change in behaviour of the protocol establishing the security of the connection with ICS is causing authentication failures.
"We are aware that some users have removed the update to successfully restore connectivity. We recommend any decision to remove the security update is informed by an appropriate risk assessment and analysis.
"Additional security controls to limit any risk associated with the removal of the patch such as the use of standalone machines should be considered."