Officials say 712 people died of the illness in the last 24 hours, pushing the total tally to 8215, well over double that seen in anywhere else in the world.

New infections rose by 6153 to 80,539.

The number of cases is nudging close to the more than 81,000 infections recorded in China where the pandemic began.

The relentless rise in Italy is despite stringent lockdown measures introduced progressively since February 23 to try to stop the spread, which authorities had hoped would be having more of an effect by now.

There had been slight declines in both new cases and deaths earlier this week, but the northern region of Lombardy, the epicentre of the outbreak, saw its numbers climb on Thursday.

"I do not know if we have hit the peak or if we have missed something ... all I can say is that I am worried," Lombardy governor Attilio Fontana told reporters, adding that the situation would soon become clearer.

"I think that in two or three days we will understand if the measures we have taken are working," he said.

However, he warned that when new cases finally receded, the government would not necessarily be able to relax the lockdown, which is due to be lifted on April 3.

"Even if the number of cases declines, I think we will have to carry on with (the restrictions) until we are quite certain that this contagion has been stopped."

The situation appeared particularly worrying in Lombardy's capital Milan, which is also Italy's financial hub, where new infections jumped by more than 800 to almost 7000.

Only the neighbouring provinces of Bergamo and Brescia have a higher number of cases.

Highlighting the scale of the drama, Bergamo said that over the last 10 years it had recorded on average of 45 deaths a week.

This ticked up to 64 at the end of February and then soared, hitting a peak of 313 deaths between March 15 and 21.

Australian Associated Press