Talking to reporters here, Naidu said the partners of UPA were leaving the "unholy alliance" because of the unilateral actions of Congress.
"Third front is possible," as Congress was diminishing and the main opposition BJP was not gaining any strength, he added.
Meanwhile, the TDP chief would undertake a 117-day 'pad-yatra' (march) through Andhra Pradesh starting from October 2 to highlight the problems of the people, party sources said.
The yatra would start at Kodangal in Mahabubnagar district of Telangana region.
