Despite Brazil having the world's second-highest death toll over the past year after the United States, the far-right leader has consistantly attacked distancing measures and downplayed the gravity of the pandemic.

While the US outbreak is ebbing, Brazil is facing its worst phase yet, pushing its hospital system to the brink.

"Enough fussing and whining. How much longer will the crying go on?" Bolsonaro told a crowd at an event on Thursday.

"How much longer will you stay at home and close everything? No one can stand it anymore. We regret the deaths, again, but we need a solution."

The Health Ministry registered 75,102 additional cases of coronavirus on Thursday, the most in a single day since July and the second-highest on record.

Brazil also recorded 1699 deaths, decreasing slightly from the previous two record days.

Brazil's surging second wave has triggered new restrictions in its capital, Brasilia, and its largest city, Sao Paulo.

Tourist mecca Rio de Janeiro on Thursday announced a city-wide curfew and early closing time for restaurants.

The federal government has been slow to purchase and distribute vaccines, with less than 3.5 per cent of the population having gotten one shot.

The government is working to obtain additional vaccines from more suppliers.

The Health Ministry is understood to be negotiating to buy 2 million additional Pfizer doses by May, 16.9 million Janssen doses by September and 63 million doses of the Moderna vaccine by January 2020.

Particularly worrying to health authorities is the emergence of a new navirus variant from the Amazon region that appears more contagious and more able to reinfect those who have already had COVID-19.

Government-affiliated medical institute Fiocruz said it had detected the Amazon, United Kingdom and South African variants spreading in various places across the country.

"We are experiencing the worst outlook for the pandemic since it started," said Gonzalo Vecina Neto, a medical doctor and former head of Brazilian health regulator Anvisa.

"Mutations are the result of the increased reproduction of the virus. The greater the number of viruses, the faster the transmission, the more mutations we have," he said

State governors and doctors have complained that the federal government has mismanaged the coronavirus crisis, as Bolsonaro has downplayed its severity and opposed lockdowns.

Nevertheless, Bolsonaro's popularity has been supported by 322 billion reais ($A74.0 billion) in emergency aid to poorer Brazilians last year.

The Senate voted on Thursday to renew the aid program at a smaller scale, handing out 250 reais per month for four months, at a cost of up to 44 billion reais.

Australian Associated Press