Especially since the last I heard they were only testing for codeine. Come to think of it, that test would likely be sensitive to any opiate. Cocaine not so much.
As mentioned, hardly a helpful allegation.
On edit, I was wrong. The relevant DAMP testing from the CASA site says:
"What drugs are tested for?
Amphetamines, cannabis, cocaine and opiates. The cut-off levels are set out in the relevant Australian Standard."