Single-family home prices dipped in June from May as the market continued to crawl along at depressed levels, a closely watched survey said on Tuesday.

The S&P/Case-Shiller composite index of 20 metropolitan areas slipped 0.1 percent on a seasonally adjusted basis. A Reuters poll of economists had expected prices to be unchanged. On a non-seasonally adjusted basis, the index rose 1.1 percent.

This month's report showed mixed signals for recovery in home prices. No cities made new lows in June 2011, and the majority of cities are seeing improved annual rates, David Blitzer, chairman of the index committee at Standard & Poor's, said in a statement.

Prices in the 20 cities fell 4.5 percent from a year ago, better than expectations for a decline of 4.6 percent.

The national index was up 0.1 percent on a seasonally adjusted basis for the second quarter compared to the first three months of the year.

An excess supply of homes, ongoing foreclosures, tight credit and weak demand have kept the housing market on the ropes and hampered the broader economic recovery.

(Reporting by Leah Schnurr; Editing by Padraic Cassidy)