Thousands of Brazilians took to the streets on Sunday in anger at moves by Congress to boost lawmaker's immunity and push for amnesty that could include former far-right president Jair Bolsonaro, convicted of trying to stage a coup.

As Brazil grapples with the fallout from the divisive Bolsonaro trial, which saw him sentenced to 27 years in prison, the conservative-majority Congress has come under fire from critics who accuse it of putting its own interests above social and economic issues.

Demonstrations have been called in over a dozen cities on Sunday, including Rio de Janeiro where octogenarian music icons Caetano Veloso, Gilberto Gil and Chico Buarque will perform a protest concert on Copacabana beach.

"We are here to protest this Congress, which is made up of criminals and corrupt people dressed as politicians, who are pushing for a law that protects them," said 34-year-old environmentalist Aline Borges at a protest in Brasilia.

On Tuesday, the lower house approved the so-called "Shielding Bill," under which lawmakers voting in a secret ballot must give the go-ahead for one of their own to be charged or arrested.

Further stoking anger, lawmakers on Wednesday fast-tracked a bill seeking amnesty for those convicted over an attack on the seats of government in January 2023 after Bolsonaro lost re-election – which could include the former president.

House Speaker Hugo Motta, of the centre-right Republicanos party, defended parliament's efforts as protection against judicial overreach.

Both bills face an uphill battle in the Senate.

President Luiz Inacio Lula da Silva has vowed to veto the amnesty bill.

He also said the "Shielding Bill" was not the kind of "serious matter" that lawmakers should be dealing with. (AFP)