An emotional Eduardo Cunha, who had already been suspended from his speakership duties, said with a cracking voice that he was the victim of persecution for starting the process to impeach President Dilma Rousseff, who has been suspended since 12 May.

"Only my resignation can put an end to this endless instability. The lower house cannot bear to wait forever," Cunha told reporters in a hastily called news conference.

Interim President Michel Temer, who replaced Rousseff while she stands trial in the Senate, now faces the tough task of forging consensus from his broad centre-right coalition on new leadership.