The tape, obtained by Joesley Batista, chairman of the world's biggest meat exporter JBS, was made public by prosecutors after it was leaked to Brazil's O Globo newspaper on Wednesday evening.

In it, the president appears to agree to arrangements Batista says he has made to silence jailed former House speaker Eduardo Cunha and an associate. He also appears to condone Batista's actions to silence two judges overseeing a separate investigation into Batista's sprawling global empire.

To the disclosure of payments to Cunha, Temer is heard saying "that has to continue, OK?". To the revelation of a scheme to keep the judges from pressuring Batista, Temer asks "are you holding both of them back?", which Batista confirms before the president says the equivalent of "excellent, excellent".

Temer, having said on Thursday that he would support a full investigation into the allegations, concluded after hearing the tape that there was nothing in it to incriminate him and that the investigation should be shelved, a presidential aide told Reuters.

Publicly, however, Temer rejected calls to resign as people returned to the streets of Rio de Janeiro, Sao Paulo and the capital Brasilia with renewed vigour to call for fresh elections and his resignation and imprisonment.

In a nationally televised address, Temer, who ascended to the top job only last year after the impeachment of Dilma Rousseff, was defiant. Raising his voice, he said efforts to mend Brazil's economy - including an austerity program and unpopular pension reforms - could be put at risk if he stepped down.

"I will not resign," he said emphatically. "I did not buy anyone's silence."

However, as federal police raided politicians' homes, calls for him to quit multiplied in Congress, where a second request for his impeachment was tabled.

"The country is in a state of shock," Marina Silva, a former environment minister and presidential aspirant, said in a video posted on Facebook. "The president of the republic is no longer in any condition to govern Brazil."

But governing amid scandal is nothing new for Temer, who has seen several cabinet members forced to resign over the extensive three-year-old Operation Car Wash. The operation sprawled from an investigation into money laundering, through a petrol station, in connection to building contracts at the state-run energy company Petrobras, and has expanded to ensnare several top businessmen and politicians.

Temer is also a subject of other investigations, including one into how his joint party ticket with Rousseff (he first came to power as vice-president) was funded, which could void the results of the 2014 election. He is accused of negotiating a $A50 million bribe in 2010 for his party, the PMDB, a claim that he also denies.

But the newest scandal around Temer appears to be more destabilising, raising the possibility of even greater turmoil.

If Temer resigns, his term will be completed by the next in line, Rodrigo Maia, speaker of the Lower House, who is facing his own federal graft investigation.

New elections can only be called after the current term ends in 2018 or if the previous election is annulled. In any case, one of the leading 2018 candidates, former president Luis Inacio Lula da Silva, is himself a target of several investigations.

An alternative possible candidate, Aecio Neves, runner-up in the 2014 presidential race, was suspended from the Senate on Thursday after Batista's secret recording appeared to catch him asking for 2 million reais ($800,000) for legal fees.

Batista's tape has earned him and his brother Wesley, JBS's CEO, immunity from prosecution. But the impact of their plea bargain and the 38 recorded minutes of the March 7 meeting at the president's residence are likely to reverberate for a long time to come.

with agencies