Discover Card or American Express
 

Are either of these credit cards widely accepted in OZ &/or NZ? Thanks in advance

I don't think the Discover Card is accepted at all but Amex is although because of its high charges not everywhere accept it - only in the larger outlets. I am not talking about NZ

Can't speak of those cards but I can tell you that Mastercard is. We have traveled extensively thruout OZ and NZ and used our MC without any problems.

There are American Express sgns at all major outlets in Australia, and AA markets its cards very aggressively to Aussies, also. The Discover Card is new to me (not that this means anything!) so it may be a bit more "chancy". Go with Amex.

We took our Amex and Visa last year. However, most food places only took CASH. (non sit-down restaurants)
but I don't think our Amex was any less accepted there than it is here.

I can't even use it at my local department store, Kaufmann's in Pennsylvania.