New data from Roy Morgan reveals Australian homeowners face unprecedented mortgage challenges, as another looming rate hike set to deepen the pain. A record number of homeowners are struggling to keep up with their loans, according to the research.

31.8 per cent of mortgage holders – or 1.75 million households, are now considered “at risk” of mortgage stress, while a record 23 per cent, 1.262 million, are “extremely at risk”.

Roy Morgan considers mortgage holders at risk if their repayments exceed a specific proportion of household income, based on their earnings and spending. They are classified as extremely at risk if even an interest-only repayment surpasses that threshold.

The September figures predate the impact of the Reserve Bank’s most recent cash rate hike to a 15-year high of 4.6 per cent. Another increase is expected next week, which could add hundreds of dollars to the annual repayments of millions of borrowers.

If the cash rate is hiked again to 5.1 per cent before Christmas, Roy Morgan estimates 34.3 per cent of mortgage holders, or 1.887 million Australians, would be at risk. This would be the highest rate of mortgage stress since June 2008, according to Roy Morgan chief executive Michele Levine.

The mortgage stress figure of 31.8 per cent in the three months to September is up 7.9 percentage points since January, following four Reserve Bank rate hikes this year. However, it remains below the record 35.6 per cent reached in 2008.

A rate rise next week is widely expected, with markets pricing in roughly an 80 per cent chance of an increase. This could push the tally of at-risk Australians to an estimated 1.821 million, according to Roy Morgan.