The prices of houses in many metropolitan areas across the country have fallen anew – for the sixth-straight month in March – in what experts call a sign of continued “weakness.”

According to the latest Standard & Poor’s/Case-Shiller 20-city composite index of home prices, the prices of properties in 13 out of 20 metro areas on the list went down in March compared to February figures. As for the national home price index, it slid 3.2% in the first quarter of the year compared to the final quarter of 2009.

“We’re beginning to see the beginning of weakness,” Paul Ashworth, senior economist at Capital Economics, said. He added that prices are likely to fall further as the federal government’s first-time home buyer tax credit program has now expired. “(Tax credits) have been quite a shot in the arm short term, but there’s a good chance house prices will fall again,” Ashworth stressed.

IHS Global Insight’s Patrick Newport also believes the tax credit program’s demise will lead to lower home prices, saying the Case-Shiller index could bottom next year. “You’re going to see a sharp drop in demand because the tax credit isn’t there. There is more supply. But demand has also grown because interest rates are really low and employment has picked up,” he said.

Among the metropolitan areas that posted lower home prices were Tampa, Chicago, Las Vegas, Atlanta, and New York. On the contrary, home prices rose in Los Angeles, San Francisco, and San Diego, with the last area seeing 11 straight months of home appreciation.

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