The Platinum Card from American Express gives the owner and a guest access to the Virgin Lounge in Sydney. The Platinum Card will also give you access to a Priority Pass Card which can be used as Various Bars and Restaurant in Sydney
The Virgin Lounge in Sydney has two Entries, one which is at the Front of the Airport which has Concierge Parking , and one directly after normal airport security.
The main Front Entry is obviously the best as Security is private so takes lesser time however unfortunately for American Express Card Holders this is not available to you :
The front entry is the Premium Entry which is exclusive for Gold & Platinum Velocity members & Business class guests having carry-on baggage only. I regret to advise that currently, there are no plans in the foreseeable future for Amex cardholders to use this entrance.