If you want to be an airline pilot take the Class 1 from the beginning, that way you'll be sure that you won't have any problems.
I don't think there are Australian CAA approved AME (Aviation medical examiner's) in India but I'll give you the one's that are approved from FAA :
http://ame.cami.jccbi.gov/amelist.asp
Ask them, maybe they can also do for Australia, but I'm not sure.
Cheers