WHICH OFFICE SHALL WE GO TO SUBMIT RENEWAL APPLICATION FORM OF HKSAR PASSPORT?

My mum is now in Melbourne and her HKSAR passport will soon be expired. As there are several offices of Chinese Consulate in Melbourane, which office shall we get an application/renewal form? Does she need to go there in person where submitting the form? Which office shall we submit the form or can we post it, if so, at what address? Will we receive a notification for collection when the new one is issued?
Thank you so much for your assistance.
Louise