The figure is up from 27 per cent earlier this year and represents the highest level of discounting since August 2012.
A total of £3.8bn has been knocked off the original asking prices of properties currently on the British property market.
Preston saw the highest proportion of price reductions, with 44 per cent of properties having had their asking price lowered since coming to market.
Only 29 per cent of houses in London had seen their original asking prices lowered, but that was almost double the 15 per cent recorded in February.
Commenting on the findings, Zoopla's Lawrence Hall said: “The property market typically slows in December as buyers postpone their plans until the New Year and become pre-occupied with the festive season, but these figures suggest that sellers may be being forced to rest their expectations and become more realistic in order to secure a buyer. People are well attuned to a bargain at this time of year, so homebuyers may want to capitalise on the latest raft of reductions.”