The interim government idea has been raised by the Taliban and some opposition figures, vowing that elections will he held as planned later this year.
Ghani has appeared increasingly sidelined as the United States hold talks with the Taliban aimed at ending the 17-year war.
A gathering last week in Moscow brought together the Taliban and a number of prominent Afghan figures but included no government representatives.
Afghan President Ashraf Ghani says the Taliban are welcome to set up a political office in the capital Kabul.
In a speech Monday, Ghani said Afghanistan should hold a loya jirga, or a grand traditional gathering of Afghan political and tribal leaders, to plot a course to peace.