It isn't neccessarily offensive, but very much depends on the manner in which it is said.
The Australian use of the word "wog" indicates may things, e.g. a "tummy wog' means a viral infection of the usual head for the toilet variety.
Wog is used as a general descriptive of Greek descent, just as Pom is a general U.K. descriptive.
Where I live "Ding" is the general descriptive for Italian descent.
All the terms can be used, just as calling a friend a stupid pr*ck, as terms of endearment or abuse.
So work that out ya septic.