U.S. single-family home prices rose less than expected in April, a closely watched survey said on Tuesday.

The S&P/Case-Shiller composite index of 20 metropolitan areas gained 0.2 percent in April on a seasonally adjusted basis. A Reuters poll of economists forecast a gain of 0.8 percent following gains of 1.2 percent in March.

Non-seasonally adjusted prices rose 1.1 percent in the 20 cities, compared to an expectation of a 0.8 percent rise.

"Near term economic factors favor further gains in housing," said David Blitzer, chairman of the index committee at S&P Dow Jones Indices, in a statement. "However, housing is not back to normal: prices are being supported by cash sales, low inventories and declining foreclosure and REO (Real Estate Owned) sales. First time home buyers are not back in force and qualifying for a mortgage remains challenging."

Prices in the 20 cities rose 10.8 percent year over year, shy of expectations for 11.6 percent.

The seasonally adjusted 10-city gauge was unchanged in April versus a 1.2 percent gain in March, while the non-adjusted 10-city index rose 1.0 percent in April compared to a 0.8 percent gain in March.

Year over year, the 10 city gauge also rose 10.8 percent.