A closely watched index shows U.S. home prices posted their first increase in three years in the second quarter, signalling the housing market may have turned a corner.

The Standard&Poor's/Case-Shiller's U.S. National Home Price Index released Tuesday rose nearly 3 per cent from the first quarter, though was still down almost 15 per cent from the second quarter last year.

The index measures the residential housing market by tracking prices in 20 metropolitan areas across the U.S.

U.S. home prices are still at levels not seen since early 2003.

The monthly index increased 1.4 per cent from May to June, the second straight month the index registered a gain.

It was still 15 per cent below June a year ago.