Joshua Gans and Christopher Joye from the Melbourne Business School argue that the markets for primary residential mortgage-backed securities in Australia are not operating efficiently.

"Under our proposal, the Commonwealth would guarantee the credit
worthiness of an Australian government agency, which we loosely call
‘AussieMac,’ thereby lending it Australia’s AAA credit rating. This
would allow AussieMac to issue substantial volumes of very low cost
bonds into the domestic and international capital markets. The funds
raised through issuing these bonds could be used to acquire
high-quality AAA-rated Australian home loans off the balance-sheets and
warehouse facilities of lenders (including the majors). AussieMac
would, therefore, serve to guarantee liquidity in the Australia home
loan market in the event that other private sources of capital were to
supply insufficient funding, such as is currently the case."

Australian Financial Review article

Full paper: Aussie Mac: A Policy Proposal for Australia