darl = darling
Often used for women. Can be used with friends, acquaintances, or strangers.
Example: Thanks for your help, darl.
Profanity rating: zero
This is definitely Aussie slang, not Kiwi. From my experience, it seems to be a more common expression in Queensland and the Northern Territories.
If you are not an Aussie, I'd advise against using this expression.