ROME - Italian Prime Minister Silvio Berlusconi's approval rating has risen back above 50 percent after an attack against him sparked a wave of sympathy even among opposition voters, an opinion poll showed on Sunday.

Berlusconi, 73, was struck in the face a week ago by a man who broke his nose and teeth after a rally in Milan.

An opinion poll by ISPO published in Corriere della Sera newspaper said the aggression had boosted Berlusconi's popularity to 55.9 percent, compared to 48.6 percent in mid-November.

Respected pollster Renato Mannheimer said the rise in popularity was most evident among young voters and practising Catholics. But Berlusconi's approval rating improved even among centre-left voters, with 17 percent giving a positive opinion.

The December 13 attack against Berlusconi shocked many Italians and drew comparisons to the dark years of political violence that bloodied the country in the 1970s and 1980s.

The attacker had a history of mental illness and no links to any political movement, but Berlusconi's allies blamed the assault on a climate of hatred and mud-slinging against the prime minister.

Politicians from across the spectrum have expressed their solidarity to Berlusconi and called for dialogue.

But Italy remains very polarised in its attitude towards the media tycoon.

Mannheimer said that based on a number of surveys in the past few days, between 20 to 25 percent of Italians hailed the attacker, 42-year-old Massimo Tartaglia, believing that Berlusconi is dangerous for the country.