Brazils Congress was accused Thursday of seeking to rush into law an amnesty that would let lawmakers off the hook from a ballooning corruption probe.

The lower house of Congress debated a measure that would ostensibly toughen laws against election campaign slush funds but might also stipulate that the rules do not apply to existing cases.

Many in Brazil were shocked because Congress was urgently debating the effective amnesty for such cases just as a giant bribery and embezzlement probe is to expand.

The lower house had planned a vote on the new law for Thursday but after coming under intense pressure rescheduled for next Tuesday.

House Speaker Rodrigo Maia said the delay was needed "so as not to vote in a hurry, for or against, or without careful analysis."

Large numbers of lawmakers have been linked to a huge corruption scheme at state oil company Petrobras and other big firms in which politicians were paid bribes disguised as election campaign donations.

Now investigators running the probe, codenamed Carwash, are set to name more names. More than 70 executives from the huge Brazilian construction company Odebrecht -- which was at the heart of illegal payments to politicians -- are about to sign plea bargains with prosecutors.

The threat of Odebrecht spilling the beans is thought to have alarmed many in the capital Brasilia, where even President Michel Temer is reported to have taken an undeclared donation from the company.

A storm of criticism broke out at Congress' maneuvers Thursday, led by the head of the Carwash probe, Judge Sergio Moro, who warned of a threat to democracy.

"To amnesty corrupt conduct and laundering would impact not only on investigations and cases that have already been judged in Carwash, but on the internal and external integrity and credibility of the state of law and of Brazilian democracy, with unpredictable consequences," he said in a statement.

Ricardo Noblat, one of the main columnists for O Globo newspaper, part of the nation's dominant media group, described the proposed congressional vote as "a coup against Carwash."

But Maia denied accusations that Congress was acting irresponsibly and simply to create an amnesty for itself.

"This is not under discussion..., that's a twisting of words to create a polemic that weakens the House," he told journalists.

"It's obvious that no deputy will vote for this bill without listening to the voters. We represent Brazilian society."