Ahmad heads the Fatah delegation and Mousa Abu Marzouk leads the Hamas delegation, al-Arabiya reported.
The officials arrived in Cairo Sunday and were to begin talks Monday, the network said.
An Egyptian official told Ahram Online the talks will help to lay down the mechanism for the forming of a government.
Ahmad urged caution about statements recently made by Mahmoud al-Zahar, senior Hamas leader in Gaza, who said the new government will refuse to recognize Israel and is not bound by any agreement Palestinian President Mahmoud Abbas has with Israel, Israel Radio said.
The meeting was to focus on "how we begin implementing what we have agreed upon within the framework of the reconciliation accord," Ahmad told the Kuwaiti news agency KUNA Monday.
He said Abbas will have the final say on the formation of the new government.
Abbas who was elected in 2005 has said he does not intend to run for president in the next election.