A senior leader of Egypt's Muslim Brotherhood says mass death sentences against him and other members of the group will result in the downfall of military-backed authorities.

Mohamed Badie, who is among the 683 people receiving the death sentence, says the regime is on the brink of collapse.

He described the verdict as “the last nail in the coffin of those who ousted the country’s first democratically-elected President, Mohamed Morsi.”

On Monday, a court in Minya handed death penalty to Brotherhood members on the charge of inciting violence after Morsi was overthrown by the military.

The hasty verdict has been slammed by UN High Commissioner for Human Rights, Navi Pillay, who says it is a clear violation of international law. Pillay has expressed regret in a statement, saying the case shows that justice in Egypt is increasingly trampled upon.

Also back in March, the same court handed death sentence to 529 other Brotherhood supporters.

The developments come as protests continue across Egypt against the presidential candidacy of former army chief, Abdel Fatah el-Sisi.

Sisi led the overthrow of Morsi, suspended the constitution and dissolved the parliament in July last year. He is also accused of leading a severe crackdown against the supporters of Morsi and the Brotherhood movement.

Hundreds of supporters of the group have been killed in clashes with Egypt army over the past few months.