The High Authority of the Constituent Assembly has invited National Salvation Front leaders for a meeting to discuss their objections to the draft constitution and how to reach a national consensus.
The authority has invited Mohamed ElBaradei, founder of the Constitution Party; Sayed El-Badawi, head of the Wafd Party; Hamdeen Sabahi, leading member of the Egyptian Popular Current, and Amr Moussa, head of the Egyptian Conference Party.
The meeting will take place on Friday, one day before the second phase of voting in the constitutional referendum.
The first phase of voting took place on Saturday in 10 governorates. Unofficial results show 56.5 per cent voted 'Yes'.
The remaining 17 governorates will vote on 22 December.
The National Salvation Front is the main opposition coalition formed after the draft constitution was approved by President Morsi on 1 December.
Headed by ElBaradei and former presidential candidates Hamdeen Sabbahi and Amr Moussa, the front called for a 'No' vote in the poll. The front has claimed 66 per cent voted 'No' in the referendum's first phase.