The amount Australians owe on their mortgages has notched up its fastest annual growth for three and half years.

The figures add weight to the comment by the RBA in its Financial Stability Review last week that housing credit has become “unbalanced”.

And they will encourage calls for the RBA to use “macroprudential” tools – rules and regulations – rather than just interest rates to rein in lending and prevent a dangerous boom/bust cycle in the housing market.

Housing debt rose by $7.7 billion or 0.6 per cent, between July and August.

That lifted annual growth from 6.5 per cent to 6.7 per cent, its fastest rise since early 2011.

Loans to home buyers rose 0.4 per cent, or $3.7 billion, to $918.8 billion.

But the value of debts owed by housing investors surged at twice that rate in August, lifting by 0.8 per cent, or $3.7 billion, to $417.1 billion.

The rise in the six months to August, 9.9 per cent on an annualised basis, was the fastest since 2007 before the global crisis bit into banks’ ability to lend.

If growth continues at its August pace, total housing credit will rise by another $113 billion to reach $1.5 trillion around October next year.

The figures from the RBA on Tuesday don’t include cross-border lending, such as loans made by the offshore branches of Australian banks to buy properties in Australia.

Other measures of credit in the RBA’s figures were more subdued.

Credit to businesses, aside from residential property loans, was unchanged in August with annual growth of 3.2 per cent barely beating consumer prices.

And other lending to households, which includes loans to buy shares as well as traditional consumer spending, was up only 0.2 per cent, with annual growth at 1.1 per cent.

By Garry Shilson-Josling