Insurance for an Aussie.

Hi,

Can someone help or give me the right direction to travel insurance. I will be heading to Vietnam after stopping in other countries of Asia. But I want to know whether to get my travel insurance here in Australia or in Vietnam. I know I will still need some sort of insurance on my way to Vietnam. But I know that most or mainly all travel insurance companies only do a maximum of 1 year. So would like to know when that policy expire would there be any places for me to keep obtaining a travel insurance while residing in Vietnam. As I know its expensive if I was to keep on renewing or buying a new policy after each one expire in Australia via online.

Thanks in advance.

P.s. I will be staying in Hanoi so if any aussies that is currently living there and under any insurance or how they went about with it when arriving into Vietnam would be helpful