The new Libya flag belongs to the National Transitional Council, which was recognised in July by Turkey as the legitimate representative of the Libyan people.
Another opposition group hauled down Gaddafi regime's flag at the Libyan consulate in Istanbul and flew the council's flag instead, an AFP photographer at the scene said.
A group of some 40 people came to the consulate and Abdulmecit Ali Said, the Libyan consul allowed some 10 of them in, to change the flag.
Opposition groups were also shown staging a protest at the Libyan embassy in Ankara, tearing down the pictures of Gaddafi. NTV broadcasting live showed a crowd in the embassy but did not say how many people were involved.
Dissidents did not allow Libya's Ambassador to Ankara, Ziyad Adham Al-Muntaser, to speak to the media, arguing that he was pro-Gaddafi, reported NTV.
The celebrations at the embassy began after Libyan rebels entered the heart of Tripoli in a final drive to oust Gaddafi.