The campaign of presidential candidate Hamdeen Sabahi has sent its legal advisor to the Presidential Elections Commission (PEC) to file a formal complaint against the PEC's decision to extend Egypt's election by an extra day.
The decision to extend the voting until Wednesday was in response to calls by "large swaths of the people" who were not able to cast their ballots during scheduled hours, a statement by the PEC said.
It added that the intense midday heat meant larger numbers of voters went at night, but it was not possible to extend voting later in the evening.
The commission said earlier that there were no plans to extend the voting time and officials have denied that turnout through the second polling day was low.
Ahram Online reporters have reported a noticeably low turnout across several polling stations in Cairo on Monday and earlier on Tuesday. Several media reports have also reported low turnout.