Rome: Prime Minister Silvio Berlusconi's popularity is declining because of a "defamatory" campaign against him. However, he remains one of Europe's most popular leaders, Industry Minister Claudio Scajola said.

Berlusconi's approval rating fell to 49 per cent in an IPR Marketing poll released on Wednesday, the lowest since he returned to power in May 2008.

Confidence in Berlusconi fell from 53 per cent the previous month, IPR said in the poll for the website of newspaper la Repubblica.

The decline in Berlusconi's popularity coincides with two months of press reports linking the Italian Premier to young women and paid escorts.

Wednesday's L'Espresso, a news magazine that belongs to the same publishing group as Repubblica, published for a second day audio of conversations of Patrizia D'Addario, a woman who said she was paid to attend parties with Berlusconi.

The recordings describe intimate details of D'Addario allegedly spending the night with him at his Rome residence.

"There is a defamatory campaign against him," Scajola told reporters in Rome, when asked how he explained the fall in the prime minister's popularity.

"Even with this defamatory, awful, campaign that is damaging the image of our country, Silvio Berlusconi remains the leader with the broadest support in Europe."

French President Nicolas Sarkozy saw his approval rating fall to 45 per cent in a July 20 poll carried out by Ipsos.

UK Prime Minister Gordon Brown had an approval rating of 24 per cent in a July 17 YouGov Plc poll for the Sunday Times.