The credit quality of the bedrock of the Australian banking sector's asset base looks compromised, with the central bank alert to the drag of debt on household spending. While true at any point in time, it's exceptional for the governor of the Reserve Bank of Australia, Phillip Lowe, to lend such weight to the theme as he did in a talk to the Australia-Canada Economic Leadership Forum in Sydney yesterday.  "In Australia, the household sector is coping reasonably well with the high levels of debt," Lowe said, before rushing to qualify this observation. "But there are some signs that debt levels are affecting household spending. In aggregate, households are carrying more debt than they have before and, at the same time, they are experiencing slower growth in their nominal incomes than they have for some decades. "For many, this is a sobering combination."Lowe said that, "reflecting this, our latest forecasts were prepared on the basis that growth in consumption was unlikely to run ahead of growth in household income over the next couple of years."In other words the household saving rate was likely to remain constant. This is a bit different from recent years, over which the saving rate had trended down slowly."These trends, he said, "[are] ... the key uncertainties around our central scenario for the Australian economy. "We are still learning how households respond to higher debt levels and lower nominal income growth."