Weeds
A weed is any plant that is not indigenous to a certain area, and is self-propogating. Problem weeds propogate themselves at the expense of the local flora, thereby reducing biodiversity and harming local ecosystems. Many weeds are garden escapees.
The very definition of a weed means that they are site-specific. ie. A plant may be local to Sydney, be a weed in Melbourne and not be a problem in Perth. Thus there is no hard & fast list that people can consult.
If you have any concerns about plants that may have weed potential in your area, contact your local Council or local Department of Agriculture.