Citigroup Chief Economist Willem Buiter says Australia is experiencing "a spectacular housing bubble" that needs to be addressed with tougher regulatory measures – something we've noted time and time again.

A shortage of housing, coupled with record-low interest rates, has made Sydney the world's most second-most expensive property market. The city's home prices jumped 16% in the 12 months through April, stoking record household debt and putting home ownership out of the reach of many.

"It had better be focused on immediately, to try and tether a soft housing landing," Buiter told reporters in Sydney Wednesday, according to Bloomberg. "Clearly if these things are not managed well they can be a trigger for a cyclical downturn."

Australia's biggest banks have been tightening their lending standards under pressure from regulators, making home loans for investors and interest-only mortgages more expensive, Bloomberg reported.