The World Health Organization on Sunday saluted Italy's "genuine sacrifices" after the government put a quarter of the population under lockdown to try to halt the spread of the novel coronavirus.

Over 15 million people in northern Italy woke on Sunday to find themselves cut off from the rest of the country, after the government imposed strict measures to slow the epidemic.

Prime Minister Giuseppe Conte decided to limit movement in and out of the north, including Venice and the financial capital Milan, for nearly a month.

"The government & the people of Italy are taking bold, courageous steps aimed at slowing the spread of the #coronavirus & protecting their country & world," WHO director-general Tedros Adhanom Ghebreyesus said in a tweet.

"They are making genuine sacrifices. @WHO stands in solidarity with Italy & is here to continue supporting you."

With more than 230 fatalities, Italy has recorded the most deaths from the COVID-19 disease of any country outside China, where the outbreak began in December.

Rome's new rules came shortly after the news the number of people infected had jumped by over 1,200 in a 24-hour period.

"@WHO stands in solidarity with Italy & is here to continue supporting you," the director-general said.

Later the same day, Italy's Sports Minister Vincenzo Spadafora called for an immediate suspension of the Serie A season due to the coronavirus outbreak that has killed 233 people in the country.

"It makes no sense right now, as we ask citizens to make enormous sacrifices to prevent the spread of the virus, to endanger the lives of players, referees, coaching staff and fans who will surely gather to watch the matches, by not temporarily suspending football," he wrote in a statement on his Facebook page.