Polygamist Muslims rorting welfare system, Hanson says, page-7

But they are not rorting. In Australia a man can only legally have one wife. Therefore Centrelink can only legally identify one woman as being the wife of any one man. If a man actually has some more women who are regarded in the community as his wives Centrelink would be breaking the law if they identified them as such. Therefore they can only be treated as single women/mothers.
That is our system and the welfare rules are not being broken.
Dave R.