Not many details about this offer yet, but Amex Australia just posted this on their FB…
Jetting off for the holidays? Spend $3 or more on your bank issued American Express Card at Gloria Jean’s coffees in Sydney and Melbourne airports, and enjoy a complementary coffee. See in store for more details.
it's on the Qantas Frequent Flyer Member Specials page.
Important information:
Offer valid for one regular classic coffee with minimum $3 purchase on bank issued American Express Cards only (cards issued by American Express are excluded from the offer), from Gloria Jean’s Coffees™ outlets in Sydney Domestic and International Airports and Melbourne Domestic Airport. Offer valid until the 29th of February, 2012. A Classic Coffee includes the Cappuccino, Caffe Latte, Flat White, Long Black or Long White. Not to be used in conjunction with any other offer. The complimentary coffee is offered by American Express. These cards are not issued, offered or provided by Qantas. American Express® is the registered trademark of American Express Limited (Registered office, 12 Vessey Street, New York 10285,USA).