Lawmakers this week avoided political turmoil when they agreed to the structure of a panel tasked with drafting the country's first post-revolution constitution.
Moussa, a former presidential candidate and one-time secretary-general of the Arab League, said the development was a "positive step" for Egypt that he said could lead to a panel making decisions representative of the country's post-Mubarak constituency, Egyptian news service al-Ahram reports.
The majority of the seats on the constitutional panel were awarded to the Muslim Brotherhood's Freedom and Justice Party and the Salafist al-Nour Party, two Islamist groups dominating the country's political landscape.
Some lawmakers had objected to the dominance of Islamic parties on the constitutional panel.
Moussa placed fifth in the first round of Egyptian elections last month. Later this month, Egyptians choose between FJP leader Mohammed Morsi against Ahmed Shafiq, the last prime minister to serve under ousted President Hosni Mubarak.