Housing boom gains in Sydney and Melbourne, made through the pandemic, could be wiped out by July next year, as higher interest rate rises trigger a sharper decline in prices, experts say.

The CoreLogic home value index for June shows Sydney house prices have dropped by 1.6 per cent in June, faster than monthly declines seen during the 1980s recession and close to the price falls recorded during the 2018 to 2019 downturn, said Shane Oliver, AMP Capital chief economist.