Brazilian President Jair Bolsonaro has passed a law that makes wearing masks mandatory in public during the coronavirus pandemic.
However, it has banned its use in stores, churches and schools.
In a social media broadcast, Bolsonaro said people could have been fined for not wearing a mask at home.
It has refused to acknowledge the severity of the Covid-19 outbreak in Brazil, despite having the second highest number of cases and deaths in the world.
The virus has infected nearly 1.5 million people and has killed 61,884 there since the end of February, according to data compiled by Johns Hopkins University.
BBC correspondent in South America Katy Watson says Jair Bolsonaro has never been very concerned with the masks, a health recommendation that has become highly politicized, as has much of the management of the coronavirus crisis in Brazil. .
Even when the use of masks has become mandatory, not everyone has observed the rules, and the application is usually quite lax, adds our correspondent.
The bill passed by the Chamber of Deputies included an article saying that people had to wear masks in “commercial and industrial establishments, religious temples, teaching premises and also closed places where people gather.”
On Friday, Bolsonaro vetoed the article, arguing that it could lead to a violation of property rights.
He also vetoed another who required the distribution of masks to the poor.
Congress has 30 days to override vetoes by an absolute majority of votes.
Last month, a judge ordered the president to wear a mask in public, something he has often refused to do. However, the order was rescinded by another court.
Bolsonaro has insisted that quarantine and social distancing are not necessary to combat the coronavirus and will only harm the fragile Brazilian economy.
On Thursday night, bars were allowed to open in Rio de Janeiro, where more than 6,600 people died from Covid-19.
Federal Congressman David Miranda posted a photograph showing dozens of people drinking on a street in the city’s Leblon district without appearing to be wearing masks or observing social alienation.
“An announced tragedy,” he tweeted. “[Rio de Janeiro Mayor Marcelo] Crivella’s decision to open the doors of business will have a high cost. “
Crivella’s office told Reuters news agency that law enforcement personnel had asked several establishments to close on Thursday for allowing crowds to gather.