Weird. A supplier we've had for many years no longer puts their ABN on either their documents or their website. The ABN they used to put on their documents is still active, according to ABN Lookup.
If it's an oversight, it's a weird one. But we're not sending them a payment including GST until they tell us their ABN.
re: #SysadminLive vs suppliers vs ATO
@futzle
Depending on how much you hate them and/or yourself, you could also do the withholding thing