Australian Law!

[Miss-taken]

A friend of mine's father has just died and he has lived in Australia for the past 30ish years (my friend and her sister have always lived in the UK).
The father has been living with his girlfriend for the past 25 years which would make (well in the UK anyway) her his commonlaw wife.
My friend and her sister had lost regular contact with their father but are obviously none the less upset about his death.
My question is- would they have any claim on his estate or would it go automatically go to his common law wife?
I know under UK law there is no such thing as a 'commonlaw wife' but have no idea about Australia!

Can anyone help??