Brazilian president took off the gloves on Tuesday, branding her vice-president a traitor and coup-plotter ahead of an impeachment vote in Congress.

In a blistering speech, Dilma Rousseff, 68, charged: "If there were any doubts about my reporting that a coup is under way, there can't be now."

Referring to Monday's leak of an audio recording in which Vice-President Michel Temer practices the speech he would make if Rousseff is impeached, the president said: "The conspirators' mask has slipped.

"We are living in strange and worrying times, times of a coup, and of pretending, and betrayal of trust," she said in the capital Brasilia.

"Yesterday, they used the pretense of a leak to give the order for the conspiracy."

Rousseff is in the final stretch of a bruising attempt to save her presidency from impeachment on charges that she illegally manipulated government accounts to mask the effects of recession during her 2014 re-election.

Temer, who will take over if Rousseff is impeached, countered that a war was being waged against him on both a personal and professional level.

"I'm not waging war, I'm defending myself," he told Globo News.

But making it clear he was ready to step in Rousseff's shoes, Temer, 75, added: "Without being pretentious, but with much modesty, I must say that I have a lot of experience in public life."

After a congressional committee voted to recommend Rousseff's ousting in chaotic and bad-tempered scenes late on Monday, the stage was set for a weekend showdown in the full lower house, with a party once in the ruling coalition set to cast a ballot against her.

Scramble for votes

Deputies were due to start debating on Friday, with a decisive vote on Sunday, officials said.

If the house reaches a two-thirds majority, or 342 deputies, Rousseff's case will be sent to the Senate. Anything less, and Rousseff can continue in the job.

The latest survey of the 513 deputies in the lower house by Estadao daily showed 300 favoring impeachment and 125 opposed. That left the result in the hands of the 88 deputies still undecided or not stating a position.

Then, after hours of meetings, the Progressive Party announced it has decided to pull out of the ruling coalition, and that most of its 47 lawmakers will vote for her to be impeached.