Interest bills are swallowing up a record share of our income, according to Reserve Bank figures being kicked around by the Opposition. They show the interest paid on mortgages and consumer debt – credit, store cards and personal loans – in June hit 11.4% of disposable income.

The figure is significantly higher than the 9% paid under Labor in the high interest rate days of the late 80s and early 90s. Interest paid on mortgages is now 9.1% of household disposable income, compared with 5.6% when the Howard Government took office in March 1996.

And a second set of figures, Deutsche Bank’s Financial Obligations Ratio, shows household debt has climbed to a record 171% of household income. It says households forked out an all-time high 21% of after-tax income on regular bills such as mortgage payments, insurance premiums, council rates and rent in the June quarter. Twenty years ago the ratio was just 10%.

All of which guarantees that interest rates and housing affordability continue to be crucial Question Time topics.

Both sides of Parliament had fun with Ian Macfarlane’s comments yesterday – Labor playing the PM’s 2004 “Who do you trust to keep interest rates low?” line back at the Government, which accused the Opposition of selective quoting.

There’s no doubt that debt, mortgage debt, is a potent political weapon. It’s been the Government’s. Labor is trying to seize it now.

Labor is pointing to the cost of mortgage repayments and highlighting increasing repossessions.

At the same time, too, they are warning that the Government’s demand that the states release more land will hit existing homeowners as much as it will help home buyers.

But the full implications of any such policy are being missed. The release of new land will require the building of new infrastructure – hospitals, schools and roads – for which the states will need to foot the bill.

We’ve been here before. Every Whitlam bore bangs on about Gough and the sewers of Western Sydney, where the Commonwealth had to step in to meet infrastructure demands.

Kim Beazley’s big on nation building, on infrastructure. Future Fund dividends give him some cash to play with in an economically credible way, too.

The interest rate battle is in an interesting state of flux and the moment, but if Labor can swing things its way, the Government’s poll hopes could go down the sewer.