The supply of housing for sale is not keeping pace with demand,the survey from Hometrack found.
Richard Donnell, Director of Research, said:
"Over April agents reported just a 2.8% increase in new homes on the market. Ineach of the last three months the growth in supply has failed to keep pace with demand and this isproviding strong upward pressure on pricing.
Would-be buyers are often sellers, and survey respondents report that many potential purchasers are delaying putting property on the market until they find a home to buy. These households are also waiting for signs of a sustained housing market recovery before registering with an agent to sell.
Together thesetwo factors are boosting demand while keeping supply scarce."
The survey also found that North London (1.3%) and South West London (1.1%) registered the strongest increases over themonth.
Outside the capital the next highest levels of growth were seen in Oxfordshire and Cambridgeshire.
House prices in London grew by 0.7% in April - the highest in the UK. Demand in the capital has grown three times faster than supply over the last quarter and this rise is driving the rate of growth across the country.
In London, homes are on the market for almost half the national rate, at just 4.6 weeks - and 95% of sellers are achieving their asking price; levels last seen in the summer of 2007.
In the rest of the country, prices increased by 0.3% month-on-month following a similar uplift in March.