A long section of a rustic retaining wall in the garden of the House of the Moralist is seen after collapsing following heavy rains in Pompeii, November 30, 2010. (Reuters/Ciro De Luca)

Two walls crumbled at the ruins of Pompeii on Wednesday, the latest of four collapses in a month at the 2,000-year-old Roman-era site whose decay has become an embarrassment for Prime Minister Silvio Berlusconi's government.

A statement from Pompeii's archaeological superintendent department said the collapse involved an area two meters (yards) high and three meters wide of the wall along one of the site's main streets, the Via Stabiana.

A small chunk of a side room in the "House of the Small Lupanar," which was not open to the public, also fell, the statement said, adding both collapses were probably due to the heavy rains of the last few days.

On Tuesday a section of a modern retaining wall in the "House of the Moralist" crumbled and on November 6 the "House of the Gladiators" collapsed, shining a spotlight on the decay of the ancient city buried by an eruption of Mount Vesuvius in 79 A.D.

Archaeologists, commentators and opposition politicians have accused Berlusconi's government of neglect and mismanagement of the UNESCO world heritage site, which has long been plagued by poor maintenance and lack of funds.

Culture Minister Sandro Bondi, who faces a no-confidence motion over the issue, says he is not to blame.

"Between September 2003 and February 2010 there have been 16 collapses at Pompeii -- so you see they don't just happen when the center-right is in government," he told Corriere della Sera on Wednesday.