PHOTO: House prices have fallen the most in a single month since the GFC

House prices dropped by their largest monthly fall since the global financial crisis in September, as a new report warns the amount home buyers can borrow could be slashed by a third if banks are forced to tighten their lending standards after the royal commission.

Figures released on Monday showed the major capital cities have not had the usual spring bounce, with Sydney house prices down 6.1 per cent from the same time last year and Melbourne prices falling 3.4 per cent year on year.

Economists have warned that house prices could fall by as much as 12 per cent from their peak from this time last year. A drop that large would turn housing into a top order issue for the looming federal election, where the Coalition and Labor will spar over housing policies – including negative gearing – in a cooling market.