"Beblawi, or anyone from the government of the coup, did not offer us any position in the government, and if they do, we will refuse," Mohamed El-Beltagi told reporters.
A senior figure in Egypt's Muslim Brotherhood said on Tuesday that talk of national reconciliation among rival parties and groups was "lies".
"We will not see national reconciliation unless it's on the basis of the ending of the military coup," Mohamed El-Beltagi, a senior figure in the Islamist movement, told reporters.
A spokesman for Egypt's interim president had said earlier that authorities expected Islamist movements to join in national reconciliation, including the Muslim Brotherhood whose Mohamed Mursi was toppled as president by the army on July 3.
"We expect most Islamic currents to participate in reconciliation ... including the Muslim Brotherhood," Ahmed Elmoslmany told reporters in Cairo.
He said the Muslim Brotherhood and the Islamist Nour Party had both been offered cabinet posts. Both groups have refused to participate in the government, although Nour has said it will advise interim Prime Minister Hazem el-Beblawi.
Voice of Russia, Reuters