Around 78 per cent of Commonwealth Bank’s customers are up to two and a half years ahead on their mortgage repayments, thanks to record low interest rates and rising prices that have given them and their banks a buffer to any house price collapse.

This is according to data released by the bank last December 31. However, numbers from the country’s major lenders by the end of March are less impressive, hence providing only a small shield to the potential bursting of the housing bubble.

According to the National Australia Bank’s first-half profit results, their customers are 14.7 monthly payments in advance on average. However, in ANZ, the proportion of their customers more than 30 days ahead of repayments fell to 40 per cent. Westpac customers who are ahead of repayments also fell to 72 per cent.

In spite of the record low interest rates, Westpac’s mortgages 90 days past due jumped 22 per cent in the six months to March 31, while ANZ’s rose up to 70 basis points across all states, most especially in mining states like Queensland and Western Australia. NAB’s bad home loans made up the bulk of a 14 per cent rise in bad debt charges in the first half.

“History would suggest that Australian house prices could remain flat for a prolonged period and perhaps even fall,” said CLSA banking analyst Brian Johnson. “But given Australian housing has been the principal source of loan growth in recent years and now comprises 43-61 per cent of major bank loan portfolios… a ‘collapse’ in ‘bubblish’ Australian house prices could be problematic for the Australian banks.”