(Adds comments about first home buyers in final 2 paragraphs)...

(Adds comments about first home buyers in final 2 paragraphs)

Australian No. 4 home lender ANZ Group (ANZ) broke with its rivals on Wednesday and said it supported regulator-recommended mortgage buffers to measure a customer's borrowing capacity, citing uncertainty around the direction of interest rates.

Under an Australian Prudential Regulation Authority (APRA) guideline, the country's main lenders must test whether a borrower could make repayments if interest rates were 3% higher before selling them a loan.

But the country's central bank has raised rates 4% since May 2022 to slow inflation, leaving thousands of home owners unable to refinance their loans under the guideline. ANZ's three larger rivals have started considering lending without applying the 3% buffer, saying it is disadvantaging some borrowers.

"Of course we should build in buffers," ANZ CEO Shayne Elliott told parliament in a regular hearing the country's main bank bosses are required to attend.

"I think 3% feels about right. We don't know what the future holds," he added.

Few people predicted the size and speed of rate hikes so far in 2022 and 2023, and "economists think there might be another 50 basis points or more", he said.

"It's completely unknown. We're very comfortable with the 3%."

Elliott said that while ANZ had noticed a slowdown in discretionary spending - including for health club memberships, streaming services and dining out - its call centres had recorded only a modest increase in borrowers struggling to make repayments.

Just A$6 of every A$1,000 ($670) owed to ANZ for a mortgage repayment was more than 90 days late, which was "better than it was before the pandemic", Elliott said.

"Good incomes mean that people absorb bigger expenses," he added. Also, household savings remained higher than before COVID-19 and lending standards had improved.

Even first home buyers who bought soon before the rate hikes, the category most exposed to higher repayments, "are performing remarkably well", Elliott said.

People coming off low fixed-rate mortgages, facing far higher variable rates, were "less stressed than the average customer," he added. "They're prepared for it. They know it's coming, it's not a surprise."

($1 = 1.4939 Australian dollars)