Egypt’s Islamists appeared set Saturday to dominate a body tasked with drafting the country’s constitution — and ultimately of setting its political course — as legislators from both houses of parliament worked to select the panel’s 100 members.

The constitution, which among other things will determine the relative powers of the president and parliament and define the role of religion and the scope of minority rights in Egypt, has been the subject of heated debate since president Hosni Mubarak’s ouster last winter.

But the process of selecting the panel was stymied Saturday when liberals and leftists from the Egyptian Bloc, which controls about 9 percent of the seats in parliament, walked out in protest. Members accused the Islamist Muslim Brotherhood, the most powerful parliamentary force with just under half the seats, of trying to pack the panel with its supporters.

Under rules approved by parliament last week, 50 of the panel’s members will be lawmakers and 50 will be other prominent Egyptian figures. According to the state-run Middle East News Agency, initial indicators showed that the Muslim Brotherhood’s political wing expected to take 25 of the seats allotted to lawmakers and ultraconservative Salafists from the Nour Party were expected to take 11, leaving just 14 seats for other parties.