The residential mortgage loan books at Aussie banks are huge, but at least regulators are remaining vigilant in their efforts to monitor the sector.

That’s the view of UBS in a research note called Housing Bubble Watch, which provided some historical perspective on the incredible growth of household mortgage debt in Australia. The bank also assessed statements made by APRA yesterday about fostering strength in the sector and raising capital ratio requirements for Aussie banks. UBS cited the Basel 1 Accord in 1988 as a key event which kick-started the upward spiral in mortgage debt.