A man wearing a face mask stands by the coffin of his mother during a funeral service in the closed cemetery of Seriate, near Bergamo, Lombardy, on March 20, 2020 during the country's lockdown aimed at stopping the spread of the COVID-19 (new coronavirus) pandemic.

The number of coronavirus cases in Italy is probably 10 times higher than the official tally, the head of the agency collating the data said on Tuesday as the government readied new measures to force people to stay at home.

Italy has seen more fatalities than any other country, with latest figures showing that 6,077 people have died from the infection in barely a month, while the number of confirmed cases has hit 64,000.

However, testing for the disease has often been limited to people seeking hospital care, meaning that thousands of infections have certainly gone undetected.

"A ratio of one certified case out of every 10 is credible," Angelo Borrelli, the head of the Civil Protection Agency, told La Repubblica newspaper, indicating he believed as many as 640,000 people could have been infected.

After four weeks of steep increases in deaths and cases, the growth rate has eased since Sunday, raising hopes that the most aggressive phase of the contagion might be over.

"The official numbers of the last two days indicate a slowdown in the epidemic," said Giorgio Gori, the mayor of Bergamo, a small city in the northern region of Lombardy that has suffered the heaviest death toll in the country.

"I am being cautious because I do not want to delude myself, but at the same time I have a lot of hope that two whole weeks of lockdown plus increasingly restrictive measures are producing results," he told a group of foreign reporters.

The government has shut down all non-essential business until April 3 and the cabinet was due to meet later on Tuesday to tighten the screws still further, including hiking fines for people violating the shutdown to up to 4,000 euros ($4,300) from a maximum 206 euros at present.