The Lower House Acting Speaker has annulled last month's vote allowing senators to decide her fate because of procedural flaws.
But the embattled president has urged caution.
Dilma Rousseff was expecting to be impeached by Brazil's congress over allegations she breached budgetary rules in government attempts to boost the country's flagging economy and illegally hid the scale of the budget deficit.
The Senate is scheduled to vote on Wednesday on whether to start an impeachment trial.
But there's been a dramatic late intervention by Brazil's acting Lower House speaker.
He has called for a new vote in the chamber, citing irregularities in last month's ballot that voted overwhelmingly in favour of the impeachment process going ahead.
Workers Party Senator Paulo Paim broke the news to the chamber.
"We are receiving information that the current speaker of the lower house of Congress, Waldir Maranhao, has just requested the return of the impeachment process, meaning the annulment of the vote on the 17th of April."
According to the BBC's Brazil correspondent, Julia Carnero, the acting speaker had decided that MPs who spoke to the media before the impeachment vote breached procedures.
"And it was very clear publicly if they vote yes or no and that had compromised the result so it would have influenced other congressmen in voting one way or another in what was supposed to be a neutral and free vote according to each one's choice."
Word soon reached Dilma Rousseff supporters at a presidential rally...
After finding out the Speaker's ruling herself via mobile phone, the President urged caution.
"People, I don't have this information officially. I am speaking here because I could not in any way pretend I was not aware of the same thing you are. But it is not official. I do not know the consequences. Please be cautious. We live in a period of trickeries. Trickeries."
After battling for her political survival for months as Opposition MPs aggressively push for her to be ousted, Dilma Rousseff is also under no illusions about the fight ahead.
"And I believe that we must continue to realise what is going on. We will only understand what is going on if we understand that firstly it is difficult, and secondly we must understand the situation to be able to fight."
Brazilians are now scrambling to understand the implications of the Speaker's shock move.
Some are questioning if could delay the process for days, or even weeks.
And, with more than 300 members of the Lower House already having voted for the impeachment, whether it could just be a temporary stay of political execution for the President.
With the country due to host the Rio Olympics in three months' time, there may still be no Dilma Rousseff to greet the dignitaries.
