Not just the value of debt – you'd expect that to rise as the population and economy grows – but the ratio of household debt to disposable income, which climbed to 186 per cent in the December quarter.

If you think that sounds a bit on the high side, you'll be right.

This figure was about 70 per cent in the early 1990s, and has been more or less constantly rising ever since, despite a brief dip after the global financial crisis. This ratio is higher here than in most countries, and foreign analysts often say it looks like a weak point in our economy.

So, should we be concerned?

While opinions vary, there aren't many analysts who dismiss the high level of debt as nothing to worry about. It is clearly a risk.

But, at the same time, it is important to look at who holds it, their assets, and how they may be affected if there is an economic shock.

The vast majority of debt is tied up in home loans, which have been growing quickly in recent years because of rising house prices and ultra-low interest rates.

Who is holding all this mortgage debt? The Reserve Bank this month said about half of it was owned by the relatively well-off, those in the top 20 per cent of income earners, who are "most able to service it".

Many borrowers have also been using this period of ultra-low interest rates to pay back their loans ahead of schedule.

The Reserve Bank said customers were, as a whole, 2½ years ahead of their scheduled mortgage repayments, giving them a strong "buffer" against a shock, such as a weaker economy. The share of bank home loans that were in trouble fell in the second half of last year, to just 0.6 per cent.

And when you compare the pile of debt with the value of house prices, things have actually improved in the past few years. The ratio of household debt to assets has dipped from 24 per cent five years ago to 22 per cent, HSBC reports.

All these facts suggest the growing pile of household debt is not causing serious problems at the moment. But it would be naive to brush off rising indebtedness as something that can be ignored.

First, it's highly unlikely house prices in the biggest cities will rise as they did in the past few years, so home owners probably can't rely on prices going up to increase their equity.

A second reason for caution is that average pay packets are growing at the slowest pace on record, so neither can borrowers rely on big pay rises to reduce their debt.

Third, interest rates are abnormally low. Borrowers should make sure they can manage their interest payments when rates rise, and it will happen eventually.

Banks are meant to test how borrowers can handle higher interest rates when they approve loans, but some did a poor job of this until early last year, regulators say.

In the rush to lend money and boost profits, some banks were assuming some borrowers' expenses would be unrealistically low, and they were failing to think about big rises in interest rates.

This sloppiness by banks has largely been corrected, the authorities say. But there may be people who received loans under much looser credit standards who will be more vulnerable to a rise in interest rates, or weakening economy.

There's no exact answer as to how much debt someone should have. But considering that our debt is on the high side, and these various risks, using this period of very low interest rates to pay off loans seems pretty sensible.