Rising rates have hit housing affordability, with the percentage of suburbs where it is cheaper to buy a house than rent one slumping to just 3.3 per cent nationally from 30 per cent before interest rates started increasing last year, new CoreLogic data shows.

The rising cost of money since May last year has pushed up mortgage repayments on a $500,000 variable-rate loan with principal and interest repayments over a 30-year term by 25.5 per cent, adding about $606 each month, according to the data provider.