They also argue that the activities of its political arm, the Freedom and Justice Party, are therefore also illegal.
During the Tuesday session, lawyers from both sides battled verbally, with the Brotherhood eventually requesting time to study court documentation and submit further evidence to support its case.
“They had an excuse before the revolution, but I do not know why they haven’t taken that step afterwards,” Abouel Fotouh, a former Brotherhood leader, said in an interview with the CBC channel.
Abouel Fotouh broke with the group after the revolution, after previously defying the Brotherhood's earlier decision not to field a presidential candidate for the 2012 elections.
The former member told media presenter Emad Adib that he had always rejected the idea of forming a political arm of the Brotherhood, arguing that the group should have maintained its primary preaching role.
“If any of its members would like to practice politics, [they] should do that away from the Muslim Brotherhood,” he added.
Earlier news reports had said that the Brotherhood would seek legal status after Parliamentary approval of a draft law on civil society organizations prepared by the Ministry of Insurance and Social Affairs.
The draft drew criticisms by NGOs and activists for potentially restricting civil society activities.