Home Affairs Minister Mwila is Acting president.
President Lungu left instruments of power with Mwila when he traveled to Malawi this morning.
The Zambian leader is in Malawi,for a meeting with his counterparts Peter Arthur Mutharika of Malawi and Filipe Jacinto Nyusi of Mozambique.
Vice president Inonge Wina is also out in UK.
According to the PF government hirachy Finance Minister is the third, followed by Justice Minister then Defence and Home Affairs.
The President has the powers to appoint any of his Ministers to act in his absence.