Old post, but figured would be useful in the future. This is from the AMEX site for platinum edge
Membership Rewards Program. Subject to the Terms and Conditions of the Membership Rewards program available
here. The following merchants have been classified as major supermarkets: Bi-Lo, Coles, Fishers, Food For Less, Fresh Provisions, Harris Farm Markets, IGA, Macro Wholefoods, Safeway, Supabarn, Thomas Dux, Woolworths. The following merchants have been classified as major petrol stations: Ampol, BP, Caltex Woolworths, Gull, Metro, Peak, Safeway Petrol, Shell, United, Woolworths Petrol, 7 Eleven.
Exceptions may apply if an individual merchant trading as one of the above named retailers does not accept American Express as a form of payment.
Purchases at major supermarket & major petrol station retailers are only eligible for additional points if the transactions are made in Australia.
Certain transactions will earn 2 points per dollar spent, including the use of foreign currency overseas and overseas online payments. Additional points for major supermakets, petrol stations and foreign currency may not apply when you use a payment account, payment aggregator, services of a third party or online retailers that sell goods for another merchant. For example a payment made to a major supermarket processed through a payment aggregator may not earn the additional points.