The lawmaker son of Brazil's far-right President Jair Bolsonaro has changed his Twitter profile picture to one of Donald Trump to protest the platform's decision to ban the US president.

Accusing Twitter of "authoritarianism", Eduardo Bolsonaro said Sunday he was "permanently" using Trump's picture.

Twitter booted Trump on Friday, two days after a violent mob of the president's supporters stormed the Capitol in Washington while lawmakers were in the process of counting and validating President-elect Joe Biden's November election victory.

Trump has repeatedly claimed he lost due to electoral fraud although he and his campaign team have provided no evidence to back up their accusations and have lost around 60 state and federal court cases aimed at overturning the vote result.

Biden, who will be sworn in as president on January 20, won more than seven million more votes than Trump and over 70 more electoral college votes too.

Brazilian Deputy Eduardo Bolsonaro, son of Brazilian President Jair Bolsonaro, shown during a 2020 political swearing-in ceremony
Brazilian Deputy Eduardo Bolsonaro, son of Brazilian President Jair Bolsonaro, shown during a 2020 political swearing-in ceremony AFP / EVARISTO SA

Eduardo Bolsonaro hit out at the "murder of freedom of expression" and questioned why Trump has been suspended from Twitter but not Venezuela's authoritarian leader Nicolas Maduro.

When his father was sworn in as president of Brazil in January 2019, there were suggestions Eduardo could be named ambassador to Washington due to his strong relationship with the Trump family.

Jair Bolsonaro was the last prominent world leader to congratulate Biden on his victory more than a month after the election.

Both seen as populists, Bolsonaro and Trump have been close allies since the Brazilian president came to power.

"Basically, what was the problem, what caused the crisis? A lack of confidence in the vote," Jair Bolsonaro said about last week's Capitol violence.

He has supported Trump's claims of being a victim of electoral fraud and also suggested that "something worse" could happen in Brazil next year when he's up for re-election if voters are allowed to cast ballots electronically.