Monti was likely to meet President Giorgio Napolitano after a Cabinet meeting late Friday and resign, the Italian news agency said.
It was expected that the budet would be approved before the meeting.
At the end of a Christmas mass for employees of his office, Monti joked that the Mayan prophecy of the end of the world was not the cause of his impending resignation.
"A year ago this government was beginning," Monti said. "Today, on the other hand, we have to end this role and the Mayan prophecy is not to blame".