Property buyers in some of Australia’s most affluent suburbs are among the most vulnerable in terms of mortgage stress, states new research from Digital Finance Analytics.

“The young affluent in plush inner suburbs living the high life are more likely to be financially derailed by rising costs than battlers in new estates on the suburban outer fringes,” said Martin North, founding principal of Digital Finance Analytics.

More than 16,000 mainland Aussie households were listed in the country’s top 20 most vulnerable postcodes. Thousands more are at risk of falling behind on mortgage repayments, revealed Digital Finance Analytics, which analysed each postcode in terms of income and debt levels.

Households in the Melbourne suburb of Toorak - where median prices are $3.5 million for houses and $845,000 for apartments - are five times more likely to default on mortgage payments than the national average.

The same probability exists in the Sydney suburb of Bondi, where median prices are approximately $2.5 million for houses and $1 million for apartments.

Other suburbs on Sydney’s North Shore were among the addresses where hundreds of households are dangerously close to a 30-day default, which is a late mortgage repayment.

“Everyone focuses on Western Australia and Queensland but there is a much broader group of households that are closer to the edge and will find it difficult to cope if interest rates go up,” said North.

Wealthier households would be disproportionately affected by even a small rate rise because they’re more likely to be supporting lavish lifestyles and grappling with bigger credit card debt. 

The probability of the top 20 households defaulting on mortgage repayments over the next 12 months ranges from about 3% to 5%. A probability rating greater than 2% was deemed “significant” by North.

Speaking to ABC News, North said the ability of wealthier households to manage their finances over the next 12 months would serve as an “acid test” for the nation.  

“How households will respond over the next 12 to 18 months, and how lenders respond and how regulators respond in a potentially rising market, is going to be the acid test of whether we end up with a property crisis, or whether we muddle our way through,” he said.