A measure of inquiries from potential buyers fell to minus 4 from 1 in March, RICS said in its monthly survey of real-estate agents published Thursday.
The stagnant picture for sales at the national level is expected to continue over the next three months as just three per cent more respondents expect to see a rise in sales over the time period.
Anecdotal evidence cites a lack of choice; uncertainty due to the calling of an early election; and the ramifications of stamp duty changes as factors hampering activity.
On the supply side, the number of new instructions to sell rose for the third month in a row - indeed at the fastest rate in the UK.
The UK housing market is continuing to slow down, with falling property sales, "stagnant" buyer demand and general election uncertainty all adding up to one of the most downbeat reports issued by surveyors since the financial crash.
However, the twelve month outlook is more optimistic with 31 per cent more respondents anticipating a pick-up in sales over the year ahead at the national level.
Some 15 per cent more respondents saw new instructions drop in April, while new buyer enquiries were unchanged nationally, having failed to see any meaningful growth since November 2016.
The report said price growth ground to a halt in East Anglia and the North East last month.
The Rics members surveyed predicted that United Kingdom property price inflation would slow during the next three months, but despite this, they were anticipating that all parts of the country would see some growth in prices during the next 12 months.
But estate agents believe house prices in all parts of the United Kingdom will grow over the next twelve months.
"Although the picture clearly does vary across the country, the bulk of the feedback we are receiving points to a fairly flat summer for both activity and prices", Rics chief economist Simon Rubinsohn said.
Sean Murphy, Managing Director, Personal Banking at Ulster Bank, says: "The local housing market appears to have entered the second quarter of the year much as it finished the first, with prices and sales rising, and the expectation that this will continue".