Mufti day (and other New Zealand words & phrases we are learning)

Today the big kids had their first "mufti day" at school. We have been learning lots of new words and phrases... here are a few.
mufti day - casual day (no uniform)
rubbish - trash
jumper - sweater/ sweatshirt
chilly-bin - cooler
sultan - raisen (Sultan Bran - a favorite at our house)
bach - vacation home
capsicum - bell pepper
knackered - tired/exhausted
togs - swimsuit
mum - mom
lollies - candy
nappies - diapers
boot - trunk
heaps - lots (we got heaps of candy)
tramping - hiking
sweet as - cool or awesome
zed - z, as in the last letter of the alphabet.
cheers - good wishes/ thanks
yeah na - this is something I have yet to fully grasp