The Mediterranean country's daily death rate is now higher than that officially reported by China at the peak of its outbreak around Wuhan's Hubei province.
Italy's previous one-day record death toll was 475 on Wednesday.
Italy has seen more than 1,500 fatalities from COVID-19 in the past three days alone.
It has now recorded the five highest one-day tolls officially registered around the world.
Italy's total number of deaths now stands and 4,032. Infections rose by nearly 6,000 to 47,021.
The nation of 60 million currently accounts for 36.6 percent of the world's coronavirus deaths.
“There are so many people walking around who have the virus and who are at risk of infecting others,” Matteo Bassetti, the director of the infectious diseases department at Genoa's San Martino clinic, told Italy's AGI news
“The 40,000 cases we are talking about could actually be 100 times higher.”
Italy's government said on Friday it is considering even further restrictions on its already locked-down population as the country reels under the continued spread of the coronavirus.
“In the next 24 to 48 hours, new restrictions are possible,” Italy's minister of regional affairs Francesco Boccia said Friday, citing the possibility of banning open-air activities.
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The presidents of regions in the north — Italy's richest and the most devastated by the virus — have been pressing Prime Minister Giuseppe Conte to clamp down even harder on the movement of people, calling for the deployment of the army to help enforce the measures.
“Unfortunately, even today the statistics aren't going in the right direction, neither in terms of new infections or in terms of deaths,” Lombardy's president Attilio Fontana told a press conference on Friday.
A list of requests by mayors throughout Lombardy would be submitted to Conte on Friday, he added.
Fontana has asked Conte to close all private and public offices, other than essential ones, as well as construction sites, and to crack down harder on people who continue to flout the quarantine.
“I tried to convince him that we have to take more rigorous measures,” Fontana told La7 television on Thursday, referring to a conversation with Conte.
“We can't joke around anymore.”
The government imposed a nationwide lockdown on March 12 and had been hoping to see the first results after two weeks.
But civil protection service chief Angelo Borrelli said Friday it was premature to think about when infections might begin to plateau.
“There are reasons to think that it could be next week or the week after,” Borrelli told reporters.
“But it is not a scientific fact.”
Italy's death rate of 8.6 percent among those registered with infections is significantly higher than in most other countries.
Medical experts have mainly attributed this to Italy's older than average population.
The overwhelming majority of Italy's fatal cases involved elderly people with at least one pre-existing condition.
The National Health Institute (ISS) said Friday that the average age of Italy first 3,200 victims was 78.5.
Almost 49 percent of them had three or more pre-existing conditions.
Just 1.2 percent of those who died had no other ailments.