Month-on-month asking prices dropped the highest ever from July to August, according to Rightmove.
Its August House price Index found that the average asking price in August 2012 was £236,260, down 2.4 per cent from £242,097 in July.
That followed a 1.7 per cent drop month-on-month from June to July.
Meanwhile, 127,992 properties were added to the market, up 0.4 per cent on August 2011.
Despite the large drop in the last two months, prices are still 2 per cent higher than they were in August 2011.
Rightmove director and housing market analyst Milles Shipside said that sellers who come to market in the middle of the summer holiday season often have an urgent reason to sell and traditionally set their asking prices aggressively lower, but added that 2.4 per cent was still a substantial drop on the average August drop of 1.1 per cent.
He said: “One would perhaps expect some sellers to have postponed their marketing plans until after the Olympic distractions, though with more ‘working from home’ it may have given them an opportunity to begin their property move a few weeks earlier in readiness for the hoped-for upturn in buyer activity in the lead up to Christmas.
“The number of new sellers is slightly up on the same period last year, though perhaps as a reflection of their urgency to sell, or to compensate for the distraction of the achievements served up by Team GB, they have dropped their asking prices more aggressively than summer sellers in previous years.”