Used in New Zealand for years (esp. by Maoris) as slang for friend.
However, it is not limited to being used between close friends. Much as the Australians are are known to use the word mate
, even if the person they are adressing is a stranger, so do New Zealanders with "bro".
It is often preceded with the word eh
(a variation of "hey") especially when used in a question.
Eh bro! Where you been?
Look at my new car. Pretty choice
C'mon bro! You comin to the game?
Nah bro. I've got to work