[also cross-posted to visa/mastercard forum]

a citibank gold card from certain markets grants access to northwest worldrooms upon presentation of the card regardless of airline/class travelling that day.

e.g.
philippines: http://www.citibank.com/philippines/...p/trcomfrt.htm
thailand:
http://www.citibank.com/thailand/cd_det.htm#WorldClub

the question is whether a citibank gold card issued from another market, say, australia or malaysia, would allow lounge access as well since the cards don't actually differ physically from market to market.

The first four numbers differs.

Sorry, but the cards do differ, look at the back of the card, you will notice that it has a phone number to call which is localized for each country, an address for citibank locally, which for thailand at least includes the country (and it also has writing in Thai), and says "outside of Thailand call... and as mentioned above, the first four numbers differ. Even within a country those numbers will deffer for different types of cards.

Some cards issued in the same country may qualify while others don't, I believe this is true in Japan as I saw a japanese family hassled about it (so I took them in as my guests, on my citibank card and my WC member card, which greatly relieved the WC agent as she couldn't explain to them that she didnt have that particular card on her list) . The Worldclub agents actually have a book (I've seen it pulled out to check) and it shows pics of the cards as well as descriptions of card type for each country (in case the card designs/types change I guess).

The thing to do is to call Citibank in your issuing country and find out if they participate.