Brazil's top federal prosecutor charged President Michel Temer on Monday with accepting bribes, the first of what is expected to be a series of formal graft charges against the deeply unpopular leader in the coming weeks.

Prosecutor-general Rodrigo Janot delivered the charges to the Supreme Court, marking a stinging blow to Temer and the first time the public prosecutor has presented charges against a sitting Brazilian president.

Under Brazilian law, the lower house of Congress must now vote on whether to allow the tribunal to try the conservative leader, who replaced impeached leftist president Dilma Rousseff just last year.

Lawmakers within Temer's coalition are confident they have the votes to block the two-thirds majority required to proceed with a trial. But they warn that support may wane if congress is forced to vote several times to protect Temer — whose popularity is languishing in single-digits — from trial.

Temer says he's innocent

Temer's office and his attorney, Antonio Mariz, did not respond to requests for comment. Temer has repeatedly said he is innocent of any wrongdoing.

Temer was charged in connection with a graft scheme involving the world's largest meatpacker, JBS SA. Executives said in plea-bargain testimony the president took nearly $5 million in bribes for resolving tax matters, freeing up loans from state-run banks and other matters.

Brazil's Prosecutor-General Rodrigo Janot gestures during a seminar on combating corruption, in Brasilia on June 19. Janot charged Temer on Monday with accepting bribes. (Ueslei Marcelino/Reuters)

Joesley Batista, one of the brothers who control JBS, recorded a conversation with Temer in which the president appears to condone bribing a potential witness. Batista also accused Temer and aides of negotiating millions of dollars in illegal donations for his Brazilian Democratic Movement Party (PMDB).

In a previously undisclosed exchange from that March conversation between Temer and Batista, the president tells the businessman that he was a major influence on the appointment of Henrique Meirelles as finance minister, the federal police said on Monday.

For more than three years, investigators in Brazil have uncovered stunning levels of corruption enveloping the political class and business elites. Much of it is centred on companies paying billions of dollars in bribes to politicians and executives at state-run enterprises for lucrative contracts.

A third of cabinet under investigation

Temer and one-third of his cabinet, as well as four former presidents and dozens of lawmakers are under investigation or already charged in the schemes.

The scandals reduce the chances that Temer can push through reforms crucial for Latin America's biggest economy to rebound from its worst recession on record.

Key lawmakers in Temer's alliance told Reuters, on condition of anonymity, they will halt work on proposed labour reforms if forced to vote on charges against the president.

Temer's supporters say they have between 250 and 300 votes in the 513-seat lower house to block a trial. But the president is expected to soon face charges of racketeering and obstruction of justice, each requiring a separate vote.

On Monday, the federal police recommended charging Temer with obstruction of justice — the first step toward a new round of charges.

Also on Monday, the federal police recommended charging Temer with obstruction of justice — the first step toward a new round of charges. (Ricardo Botelho/Associated Press)

Allies torn

Allies of Temer have been torn between whether to continue supporting the beleaguered leader or to bail because of fears that association with him could be toxic during elections next year.

Janot's 64-page decision was a blistering assessment of Temer and his actions as Brazil's top leader. Janot said bribes to Temer could have reached about $12 million over nine months, and that, in general, Temer showed a total disregard for the office.

"The circumstances of this meeting [with Batista] — at night and without any register in the official schedule of the president of the republic — reveal the intent of not leaving traces of the criminal actions already taken," wrote Janot.

Earlier Monday, Temer sought to show his government conducting business as usual, defiantly saying he wasn't going anywhere in his first comments since returning from a trip to Russia and Norway last week that was filled with gaffes and mounting bad news.

"Nothing will destroy us. Not me and not our ministers," he said during the ceremonial signing of a bill in the capital of Brasilia.

​But despite the tough talk, Temer is facing risks to his mandate on several fronts, from tanking popularity to numerous calls, some from heavyweight politicians, for him to step down.

Trip to Europe 'a disaster'

His trip last week to Russia and Norway ended up underscoring the president's problems and Brazil's diminished stature overseas, thanks to a steady stream of corruption scandals the last three years.

Few people showed up at the reception at Brazil's embassy in Moscow, no top Norwegian officials welcomed Temer at Oslo's airport and the country's prime minister, Erna Solberg, gave Temer a public lecture about the colossal "Car Wash" investigation that has upended Brazilian politics.

Launched in March 2014, the investigation into billions of dollars in inflated construction contracts and kickbacks to politicians has landed dozens of the country's elite in jail and threatens many more.

"We are very concerned about the 'Car Wash' probe," said Solberg, adding that it was important for Brazil to "clean up" corruption.

To top it off, during Temer's visit, Norway announced a 50 per cent cut in funds it pays into Brazil's Amazon rainforest fund because of increased deforestation. The increased deforestation began before Temer took power last year, but environmentalists argue his policies are aggravating the situation.

"It was a trip to distract people from the problems in politics," said Mauricio Santoro, a political scientist at the State University of Rio de Janeiro. "It ended up being a disaster."

Approval rating just 7%

Temer now also has the dubious distinction of having the lowest approval rating of a president since 1989.

The Datafolha polling institute showed over the weekend that just seven per cent of those questioned approved of Temer's administration, the worst showing since the country was embroiled in a crisis of hyper-inflation on the watch of President Jose Sarney.

Even stalwart allies have begun to abandon Temer.

Former president Fernando Henrique Cardoso, who initially supported Temer and is a key leader of the junior coalition party, said in an article published by the daily Folha de S.Paulo on Monday that the president could end the crisis by ushering in new elections sooner than the end of his mandate, which goes through 2018.