Colonel Gaddafi has called on Libyans to "go out in new million-man marches" and resist the National Transitional Council in an audio message aired on Syrian TV.
In the apparently new and very poor quality audio tape, the ousted leader said that "conditions in Libya are unbearable".
"Be courageous, rise up, go out in the streets. Raise the green flag in the skies," he said.
Meanwhile pro-Gaddafi forces have continued their resistance against the NTC in Gaddafi's hometown of Sirte, which is one of the only major region of the North African country not to be under the control of the revolutionary forces.
Humanitarian groups including the International Red Cross have warned against the potential impact on residents there, many of whom have already been forced to flee.
Fighting also continues in the town of Bani Walid, south east of Tripoli, and in some parts of the country's southern region.
While in hiding Gaddafi has made several speeches via audio tapes in an attempt to gather supporters.