I guess you probably already knew it was a blowfly! I don't know enough about them to be sure about the species yet. Some closer shots from different angles would help - then I could try and match your insect against specimens in an authoritative collection. There are at least 15 species of Calliphora (the typical blowfly genus) in the ACT, although only a few are blue. Then again, it may not belong to that genus.
This is the only photo I have unfortunately. I have a couple of photos of others taken in the garden and they look like the Brisbane flies. I assumed that the one I put on was the same. This is where I lost the plot: http://www.brisbaneinsects.com/brisbane_tachinids/index.html What confused me these flies were always on flowers such as Ozothamnus and Platysace and on this case I think its a Plantain. I have just read that blowflies use nectar as a dietary supplement so now I understand.