Sales of new single-family houses in March 2015 tumbled back down to a seasonally adjusted annual rate of 481,000, 11.4% below last month’s revised estimate of 543,000, the latest report from the U.S. Census Bureau and the Department of Housing and Urban Development.

Last month was originally posted at a seasonally adjusted annual rate of 539,000. This was the largest monthly decline in more than a year.

"The drop was worse than either we or the consensus had been expecting, and is particularly disappointing after existing sales reached an 18-month high yesterday," analysts with Capital Economics said about the new home sales report.

However, this is 19.4% above the March 2014 estimate of 403,000.

And while sales did drop, the fall is more likely to be a temporary payback after strong growth in previous months rather than a sign that housing activity is starting to cool again, the Capital Economics report explained.

The median sales price of new houses sold in March 2015 was $277,400; the average sales price was $343,300.

The seasonally adjusted estimate of new houses for sale at the end of March was 213,000. This represents a supply of 5.3 months at the current sales rate.

"The bulk of the decline came in the largest region, the South, where sales fell 15.8%. The drop here does follow a 9.3% gain in the prior month but the latest result is not good news for the region's builders," analysts with Econoday said about new home sales. Also contributing to the decline was the Northeast, but sales in this region are very small, as well as the West, a much larger region where sales were down 3.4%. Sales in the Midwest rose 5.9% in the month.

"The trend is our friend when you take a step back and see that new home sales are up significantly compared to this time last year. We also saw supply increase which will help consumers as the spring home buying season kicks off," said Bill Banfield Quicken Loans vice president.

On Wednesday, the National Association of Realtors reported that existing-homes sales surged to their highest annual rate in 18 months, showing a promising beginning to the spring homebuying season. 

According to Capital Economics, "There are plenty of reasons why sales should rebound soon. Strong employment growth, looser credit conditions and favorable mortgage affordability will all help support housing activity. What’s more, there have even been tentative signs in recent weeks of a long-overdue upturn in mortgage market activity."