After a decade in which Italian politics was dominated by showgirls and sleaze, Beppe Grillo's brand of web-based democracy and anti-corruption campaigning has been taking Italy by storm, and his movement became Sicily's biggest party in regional elections last weekend and came second in nationwide polls.

But the tousle-haired comedian and blogger has now been dragged into a very familiar sounding Italian row after he was accused of being a "medieval" sexist and no different to politician Silvio Berlusconi.

At first glance, Grillo appears the antithesis of the permatanned former prime minister, who packed his TV shows and his cabinet with showgirls and passed around a phallic statue to break the ice at his famous bunga bunga parties. But the comedian's non-sexist credentials were called into question when Federica Salsi, a local councillor representing his Five Star Movement in Bologna, appeared on a TV talk show, ignoring Grillo's strict instructions to his councillors to stay off TV and stick to the internet.

Reacting angrily to her appearance on TV, Grillo likened the lure of television to "the G-spot, which gives you an orgasm in talk-show studios. It is Andy Warhol's 15 minutes of fame. At home, your friends and relations applaud emotionally as they share the excitement of a brief moment of celebrity."

Forty-year-old Salsi was quick to fight back, calling Grillo's outburst "disappointing", adding: "He has shown himself to be a victim of the Berlusconi culture … a chauvinist like the others."

Grillo's reference to the G-spot, she said, gave "a negative connotation to a quality women have" – and that, she concluded, "is medieval, really degrading".

Salsi was backed up by another Five Star councillor, Raffaella Pirini, who said: "She did well, she said the right things."

The row vividly recalled the years in which Berlusconi's TV channels featured leering male game show hosts flirting with semi-naked dancing girls, while the tycoon-turned-politician's cabinet ministers appeared in public with attractive young women on their arm.

Since Berlusconi stepped down last November, replaced by a government of technocrats led by sober academic Mario Monti, lewd TV advertising has been toned down, Miss Italy contestants have been ordered to show less flesh and the new, female, head of the state TV network demanded daytime hosts put a stop to endless discussions of plastic surgery.

Grillo's visceral loathing of the rowdy talk shows aired nightly on Italian TV is based on the idea that they give visibility to the caste of professional politicians his movement is seeking to oust. Grillo himself was banned from state TV in 1987 after joking about government corruption, prompting him to take his routine to live audiences and build his blog into one of the world's biggest.

But his belief in online democracy, where policy is shaped by his supporters in web forums, could be challenged as more of them gain elected office and are tempted by invitations from chat shows.

Fifteen more took office as regional councillors in Sicily after regional elections last weekend, which saw Grillo's movement poll 285,000 votes to become Sicily's largest party, even if it lost out to a coalition between the centre-left and centrist parties.

After swimming the Strait of Messina to kick off a series of rallies across Sicily, Grillo told a crowd: "The police vote for us because they are fed up with driving politicians to do shopping or have sex."

Compared with a 2008 election on the island, Berlusconi's party lost 654,000 votes in the election, which came two days after he was convicted of tax fraud.

Grillo's leading candidate in Sicily said the movement would not now be tempted by backroom alliances with other parties, preferring to be "bitter spinsters who never have boyfriends". He also announced that he and his fellow councillors would hand back a portion of the inflated salaries that local politicians in Sicily are paid.

Now, with one pollster predicting that the Five Star Movement could become the biggest party in Italy, Grillo will be eagerly awaiting regional elections due in Lazio and Lombardy, where the reputations of the local authorities have been ravaged by corruption scandals.Then, next spring, national elections are due as Monti steps down. Grillo has not stood for office himself to date but, in a video posted on his blog this week, he called himself a "political leader" of the movement for the first time and added: "We are about to confront something extraordinary."

Sitting at a desk covered in piles of paper in front of a guitar propped against the wall, the comedian warned: "It will be an epochal change, tough, and we will make mistakes, I will make mistakes, you will accuse me of everything."

But, he asked, "instead of hammering us, give us advice, a hand, we need both".