Thousands of protesters including members of far-right groups demonstrated in central Rome on Saturday against the extension of the Covid-19 health pass system to all workplaces.
There were scuffles with police as the demonstrators took aim at the health pass, which has been a requirement to enter museums, sporting events and restaurants since August.
Although the march was authorised, several hundred people broke off from the main column and tried to march on parliament.
Police used water cannon and tear gas to stop them, arresting several protesters during clashes, the AGI news agency reported.
A separate protest took place in the capital and others in the northern city of Milan and in Cesena, central Italy.
Three weeks ago the government of Prime Minister Mario Draghi announced that the scheme would be extended to all places of work from October 15 and any employees refusing to comply faced suspension without pay.
The health pass system is already in place for all medical workers. It requires people to provide a certificate of vaccination, proof of recovery from Covid-19 or a recent negative test result.
Retiree Maria Ballarin denounced "criminal and cowardly blackmail" by the Italian state.
By not making vaccinations compulsory but forcing workers to have them "it absolves itself of any responsibility for fatal or serious consequences, but indirectly obliges people to be vaccinated in order to be able to go to work", she said.
"We were both suspended two months ago," Cosimo, one of the protesters, told AFP. He and his wife Morena are both nurses.
The couple says they have immunity and allergy problems and were exempted from the vaccination requirement by their family doctor.
But both were suspended without pay.
Stefano, who came from Como in the north to join Saturday's protest, said he would take the test. "I have to pay to work, it's absurd," he said.
Nearly 80 percent of the over-12s in Italy have been fully vaccinated, according to government statistics.
The first European country to feel the full force of the pandemic, Italy has so suffered more than 130,000 deaths.