UK house prices jumped by 2.6% in May compared with April, the sharpest month-on-month rise for over seven years.
The Halifax house price survey for May beat analyst forecasts which had predicted a 1% fall for the month.
The rise came after three successive months of property price falls, with the annual rate of decline in prices easing to 16.3%.
However, Halifax warned not to place too much weight on any one month's figures.
Nitesh Patel, Halifax housing economist said: "Historically, house prices have not moved in the same direction month after month even during a pronounced downturn.
"House sales remain substantially below their long term average and market conditions are expected to remain difficult with housing activity continuing at low levels over the coming months."
Halifax, now part of the Lloyds Banking Group, also said the average price of a home rose to £158,565.
Howard Archer, economist at Global Insight said the 2.6% rise, the sharpest month-on-month jump since October 2002, was "a real eye opener".
"The Halifax data is bound to heighten speculation that the housing market is turning as it is fuelled by sharply reduced mortgage interest rates and the substantial fall in house prices from their 2007 peak levels.
"However, we remainsceptical that house prices have bottomed out. Significantly, it is not uncommon for there to be months of rising prices when house prices are still trending down," he said.
The survey follows similarly encouraging house price figures for May from Nationwide and Hometrack.