For all the commotion raised regarding foreign investment in the housing sector, an overlooked feature is the foreign demand for mortgage and bank debts of Australia necessary to keep housing loans afloat and moving and prices rising.

Local bankers and economists say foreign investors are regularly querying about the household debt levels of Australia, who are buying debts issued by resident banks.

"It's a constant question," said Brian Redican, senior economist of Macquarie, about his exchanges with American and European investors.

"There are just lingering concerns about household debt levels and whether house prices are going to hold up in Australia."

According to Reserve Bank figures, $645 billion of deposits and wholesale debts of Australia are held by foreign investors in May, with resident banks getting about 30 per cent of their finance support from international markets.

If the worldwide markets for housing debt get pressured, for instance if another sovereign debt crisis arises in Europe, or should the household debt of Australia gets singled out by overseas investors, the local banks' ability to provide loans and lend could be narrowed significantly.

Narrowed access to credit could decrease sizes of loans, which would utterly affect prices of housing.

Total Australian mortgage debt amounts to around $1.1 trillion last April, while other debts, including credit card debts, were at $141 billion, according to RBA figures.