now I'm saying it

It is the most uniquely Kiwi piece of slang there is: "Sweet as."
(When you first arrive in this country, you hear an extra "s" on the end of the phrase).

It's used the same way I used "no problem," or "that's cool" or even just "sweet."
It can be used as a descriptive expression: "That skydive was sweet as!"
or as a statement to express a laid-back contentment: "Sweet as, bro."

There's never any indication of what it might be as sweet as, of course. The construction can also be used with just about any adjective, usually to express how intense something was.
"Yesterday it was cold as, man"
"Last night I was drunk as"
"That guy is crazy as, bro"
"Your coffee is bitter as"

Mostly, however, the "as" only goes with "sweet." And once you get used to the expression, it's quite handy.
It's sweet as.