Claims that simply increasing the number of homes in Sydney will fix the housing affordability crisis have been challenged by new modelling that shows boosting supply alone is unlikely to deliver affordable housing.

Analysis by Australian National University academics Ben Phillips and Cukkoo Joseph has identified a long-term oversupply of housing in many inner Sydney suburbs. Despite the surplus, property prices have surged in that region over the past five years.

The findings cast doubt on assertions made by many political leaders, including Premier Gladys Berejiklian, that adding new housing supply is the best way to improve affordability.

The ANU report concluded that while increasing housing supply has "some benefits" it is "unlikely in isolation to create affordable housing" in Australia.