Saadi Gaddafi made the comments in a television interview from Niger, where he fled after his father was toppled.
He said he still had many followers in Libya, including within the ruling National Transitional Council (NTC).
Col Gaddafi, who ruled Libya for four decades, was killed in October after months of conflict.
A BBC correspondent in Tripoli says the authorities are worried about possible action by Gaddafi loyalists, but the possibility of Saadi Gaddafi leading a big uprising seems remote.
In a phone interview with al-Arabiya television, Saadi Gaddafi said he wanted to return to Libya “at any minute”.
“First of all, it is not going to be an uprising limited to some areas. It will cover all the regions of the Jamahiriya and this uprising does exist and I am following and witnessing this as it grows bigger by the day,” he said, using his father’s term for Libya.
He said he was in regular contact with the army, the militias, NTC officials, and other members of the Gaddafi family.
Saadi Gaddafi escaped across the border after NTC forces overran the Libyan capital, Tripoli, in August.
In December, authorities in Mexico said they had stopped a plot by a criminal gang organisation to smuggle Saadi Gaddafi into the country.
A Canadian woman employed by engineering firm SNC-Lavalin is being held in jail in Mexico awaiting trial on charges of human trafficking.
Cynthia Vanier had originally been hired to carry out a “fact-finding mission” in June 2011.
On Friday, SNC-Lavalin announced the departures of two executives linked with the case. During Col Gaddafi’s years in power, the firm was awarded contracts worth hundreds of millions of dollars in Libya, including one to build a new airport for Benghazi.