Mass trials in the biggest Arab state have reinforced fears among human rights groups that the government and anti-Islamist judges are using all levers of power to crush opponents. Egypt's government says its judiciary is independent.
A court in April recommended the death sentence for the leader of the Muslim Brotherhood and 682 supporters, and handed down a final capital punishment ruling for 37 others, alarming the United States, the United Nations and rights groups.
The 37 had initially been sentenced to death after a trial lasting only a few days. They were part of another group of 529 Muslim Brotherhood supporters, most of whom were jailed for life in the final sentencing.
"The appealed verdict (against) the convicted was marred by falsity, an infringement of the right to defend (oneself) and an error in applying the law," state newspaper Al-Ahram quoted public prosecutor Hesham Barakat as saying with reference to the 37.
"It appears (to the public prosecutor) that the verdict is marred by flaws and (he) sees the appeal as a way to seek the rule of law which states that the accused is innocent until proven guilty in a legal trial which guarantees that he has the right to defend himself," Al-Ahram said on its website.
It said the right to defend oneself must be given in a "practical" fashion, not just "theoretically".
The appeal was also reported by state-run news agency MENA.
Turmoil has deepened since the army overthrew Egypt's first freely elected president, Mohamed Mursi of the Brotherhood, in July. Security forces have killed hundreds of Brotherhood members in the streets and arrested thousands.
Former army chief Abdel Fattah al-Sisi is widely expected to win presidential elections due on May 26-27.