The government is urging caution as the country prepares this week to restart travel: the next big step in easing the national lockdown imposed three months ago.
From Wednesday, some foreign visitors will be able to enter again and people will be able to move between regions.
But the government has insisted this is one of the most dangerous phases, urging people to abide by social distancing rules and wear masks to prevent the virus from spreading again.
There was widespread concern that the unproven claims would undermine this effort and confuse the public.
“In reality, the virus clinically no longer exists in Italy,” said Alberto Zangrillo, head of the San Raffaele Hospital in Milan, the capital of the northern Lombardy region, which has been the worst-hit by the pandemic.
“The swabs performed over the past 10 days have showed a viral load that is absolutely infinitesimal in quantitative terms compared to those carried out a month or two months ago,” he said in an interview on Rai television on Sunday.
“Someone has to take responsibility for terrorising the country”, added Zangrillo, who has also been a personal doctor to former Italian prime minister Silvio Berlusconi for around 30 years.
His words prompted cries of disbelief from other experts, and a public warning from the government.
“Pending scientific evidence to support the thesis that the virus has disappeared, I would invite those who say they are sure of it not to confuse Italians,” health ministry undersecretary Sandra Zampa said in a statement.
The director of the prestigious Spallazani infectious diseases institute in Rome, Giuseppe Ippolito, said there was no scientific proof the virus had mutated or changed in potency.
National Health Council head Franco Locatelli said he was “baffled” by Zangrillo's comments.
“It's enough to look at the number of new positive cases confirmed every day to see the persistent circulation in Italy of the new coronavirus,” he said.
International experts also weighed in on Monday.
“In a situation where the numbers of severe cases are falling, there may be time to start observing people with less severe symptoms – giving the impression that the virus is changing,” said Martin Hibberd, a professor at the London School of Hygiene and Tropical Medicine.
At least 33,500 people are known to have died from Covid-19 in Italy.