Possibly, although the main problem the OFLC had with L4D2 was that it was set in the first person, in the modern day, and that you were hacking apart living, albeit mutated, humans (if the infected had been actual "walking dead" zombies it might have got away uncensored). On the other hand, God of War 3 is played in the 3rd person, set in a mythological setting and has you (mostly) ripping apart monsters. So the OFLC are likely to treat it not quite as harshly as they did L4D2, but it's still quite possible they'd rule it R18+ material (and thus refuse it classification).
Although for my part, I don't really care about God of War 3. I bought the original game and played it for a bit, but it never held my interest, which is kind of odd because I beat Devil May Cry 1 & 2 and played 3 up until I met Agni and Rudra (being too proud to lower the difficulty, my run stopped right there. [http://tvtropes.org/pmwiki/pmwiki.php/Main/ThatOneBoss]) Maybe I'm just over 3rd person action games.