"According to my information, the chargesheet will be submitted on Monday," Harb said, without giving details, in reaction to a report on Saturday in the French daily Le Monde.
The newspaper said on its Internet site that prosecutor Daniel Bellemare in the Hariri murder probe will present his findings to pretrial judge Daniel Fransen who needs to examine them before a formal indictment can be issued.
The Lebanese government headed by Hariri's son, Saad Hariri, collapsed on Wednesday after the powerful Iranian-backed Hezbollah and its allies resigned in a dispute over the UN-backed probe.
Le Monde, citing sources close to the Special Tribunal for Lebanon based in The Hague, said that members of Hezbollah, which is backed by Iran and Syria, would be targeted in the chargesheet.
Caretaker Prime Minister Saad Al-Hariri said on Friday that Lebanon's rival political factions had no alternative to dialogue.
The showdown between Hariri and Hezbollah could lead to a protracted crisis and raised fears that sectarian tensions may spill onto the streets, fueled by regional powers who back Lebanon's opposing factions.
In his first public reaction to the collapse of the government on Wednesday, Hariri said he would support President Michel Suleiman's efforts to agree a new government but did not specify if he would be a candidate to lead it.
"There is no alternative for all of us to dialogue, and no side in Lebanon will be able to eliminate the other," Hariri said after talks with Suleiman at the president's office.
Hariri described the resignation of 11 ministers, which brought his government down, as an "unprecedented" move in Lebanese politics.
"Everybody should know that I have never sought power at any price, and that between power and the dignity of my people, I choose the dignity of Lebanon and the Lebanese," Hariri said.
"I will work to the maximum extent with the president to (help) form a new government that commits to the requirements of national consensus," Hariri added.
