Looks like a Senecio sp. Might be introduced (probably ragwort?)

http://en.wikipedia.org/wiki/Senecio

http://en.wikipedia.org/wiki/Ragwort

It looks like Senecio lautus (Variable Groundsel) which is native and very wide spread and flowers from now through to summer. There are a number of variants showing differences in leaf shape.

Looks like a Senecio to me, too.
Native Senecios are often called "Fireweeds", which is an unfair name for a perfectly good native garden plant. The dreaded fireweed is an introduced plant, Senecio madagascarensis, which can apparently be distinguished from the others by having 13 "petals".
The native Senecios, which also go by the happier commonname of "Yellowtops" are not entirely innocent. Like many popular garden plants they do contain substances which are toxic to stock and to humans. People in other countries have apparently poisoned themselves by eating the seeds or drinking infusions of the leaves.
According to Everist ("Poisonous Plants of Australia"), the native plants contain the same toxic substances, but "despite their abundance in some regions and in some seasons, few of (them) are reported to be toxic in the field. Most of them are not palatable to livestock, and, in general, seasonal conditions which favour their growth also produce large amounts of more palatable pasture plants Â" We can therefore grow them with a clear conscience.
I find Senecio lautus a very good garden plant, filling in the bare bits for much of the year and being particularly good in winter and spring. Aftet that I cut the plants back because they get straggly. Then there's another late summer flush. They are biennial, so a second cut-back in early winter produces a nice-shaped plant about 30cm x 30cm, all ready to go again. They self-seed freely, popping up in spring, so keeping the species going in the garden is a simple matter. So is the weeding out of any excess seedlings, should they appear where they might smother something smaller.
There are too many native plants which have been condemned as unsuitably poisonous for garden use. The colonial mindset was very ready to call any wild plant a weed, and yet to allow much more toxic introduced plants (autumn crocus, and daffodils for instance) to naturalise in paddocks. There should be more of us using the things that come up naturally, and perhaps finding superior garden forms which will get into mainstream gardening in Australia.
Cheers, Trish