Photos of at least two leaves and a bit of stem, basal leaves if present and of the whole plant are needed to determine the ID and whether this is a native or a nasty weed.
Richard pretty sure this is the annual chamomile plant (Matricaria chamomilla) http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=gn&name=Matricaria A medicinal herb and only occasionally naturalised in Australia - don't think it has a high weed risk
We have Matricaria chamomilla as a synonym for Matricaria discoidea, so it is already on our lists. Is this correct?
See:
https://canberra.naturemapr.org/Species/14950
Afraid not. They are separate species. Matricaria chamomilla is a misapplication of M. discoidea only in the flora used in Tasmania. https://biodiversity.org.au/nsl/services/search?product=APNI&tree.id=&name=Matricaria+discoidea&inc._scientific=&inc._cultivar=&inc._other=&max=100&display=apni&search=true ALA used to make it an alternate name, but no longer does so.