Chrysomelidae (Leaf beetles, or Tortoise beetles) is quite an extensive family with at least 153 named species in Tasmania. Many a very difficult to separate so I don't usually try to name them. I'll make an exception with this one as it is so brightly coloured and distinctively marked that it's hard to imagine it being confused with anything else.
For comparison I've also posted a photo of another leaf beetle which came to the trap last week. Note the much more subdued pattern and colouration.
Please forgive the poor quality photos. These beetles are only around 5mm (if that) in length and I'm usually photographing them while I'm still waking up.
(Click to view larger photos)