Obama also warned that he would not bargain with Republicans in Congress or offer spending cuts in return for lifting the government's borrowing limit, known as the debt ceiling, in the coming months.
"While I will negotiate over many things, I will not have another debate with this Congress over whether or not they should pay the bills that they've already racked up through the laws that they passed," the president said.
"Let me repeat. We can't not pay bills that we've already incurred. If Congress refuses to give the United States government the ability to pay these bills on time, the consequences for the entire global economy would be catastrophic, far worse than the impact of a fiscal cliff."
Within minutes of speaking to reporters in the West Wing, Obama was to leave the White House for Hawaii, where he will rejoin his family on vacation.