Brazilian President Jair Bolsonaro is struggling to make good on his key election promises

Brazilian President Jair Bolsonaro has the worst approval rating in the first three months of a first mandate since the country returned to democracy in 1985, according to survey published Sunday.

The poll by Datafolha revealed that 30 percent of Brazilians believe his government is "bad or terrible," 32 percent rank it "good or excellent" while 33 percent say it is "average."

However, 59 percent of those surveyed expect that the far-right president will show "good or excellent" management. Before he took office on January 1, that figure was 65 percent, Datafolha said.

The polling institute, which surveyed 2086 people aged 16 or over between April 2 and 3, pointed out that Bolsonaro's three-month approval rating was significantly lower than predecessors.

Leftist Dilma Rousseff recorded seven percent disapproval in 2011, while her mentor Luiz Inacio Lula da Silva had 10 percent in 2003.

In 1990, Fernando Collor, the first popularly elected president following military dictatorship, had 19 percent. He resigned in 1992 amid corruption allegations.

"I am not going to waste time commenting on a survey by Datafolha, which said I was going to lose against everybody in the second round," of October's presidential election, Bolsonaro told the Folha de Sao Paulo newspaper, owned by the same firm as Datafolha.

Bolsonaro, 64, will celebrate his 100th day in office on Wednesday. He was elected with 55 percent of the vote, against 45 percent for Fernando Haddad of the Workers Party.

But the brash ex-army captain -- nicknamed the "Trump of the tropics" for his admiration of the US president -- is struggling to make good on his key election promises to kickstart Latin America's biggest economy and stamp out corruption.