Dual citizenship to Croatia or Serbia? (I'm Australian)

Ok, I hope I can get this to make sense.

Both my father and I are looking to get dual citizenship with Croatian or possibly Serbia with our Australian one.

-Both my father and I were born in Australia.
-Grandparents both born in Osijek, Croatia (Yugoslavia).
-Family lived in Yugoslavia for 150 years (1800-1950).

I recently went to the government department in Osijek Croatia and obtained both birth certificates for my grandparents. Once i was back in Australia I went spoke to the Croatian embassy and they notified that I couldnt get citizenship because the birth certificate says they were born in Yugoslavia, but not necessary Croatian. My family were Danubeswabians (ethnically Germans) but were born in Croatia and even voted in Croatia. Because of WW2, my family left Yugoslavia with no paperwork and became Australians soon after.

If my grandparents were born (and voted) in Croatian part of Yugoslavia, wouldnt that make them Croatian? If it doesnt make them Croatian, are they now classed as Serbian? I have only 1 remaining grandparent left (who doesnt hold a passport for any country) and Im trying to find a way to be able to spend more time in the Balkans without worrying about visas.

Can anyone help?

Thanks,
AussieGuy83
Melbourne, Australia

Heya!

Have you resolved this?

I have heard of a number of people trying to do what you are doing, with the same circumstances. As I understand it from chatting to various people, nobody I know has yet been able to get Croatian Citizenship with circumstances like yours.
I also wonder if now it will be more difficult as Croatia is now a member of the EU.

Sorry I can not help, but I do live in Croatia so if you need me to ask around for anything, you can reach me here chasingthedonkey.com/contact/

Hi,
I'm Canadian but obtained Croatia dual citizenship through my mother. The reason is she was born on the territory that is now the republic of Croatia. It was then Jugoslavia, but it doesn't matter. I and her obtained her birth certificate physically! We went to the office that held the birth certificate. That document essentially entitled her a citizen of Croatia, basically automatically. Because of this fact, and that I am her son, which I proved, I obtained the right to Croatian citizenship. However, it took me about 3 years. In your case the fact that your father (and grandfather) is ethnic German, I don't believe is relevant. However, your father was not literally born in Croatia (I think). Therefore, your father cannot claim citizenship directly, but perhaps via your grandfather (I hope he is alive). My advice is to have your grandfather, if he is alive to legally obtain citizenship which would be his right, after all it is the country of his birth, therefore your father through your grandfather claims it and yourself through your father. Honestly, it could take years, perhaps now that Croatia is in the EU, it will be better.
Good Luck!