Support for Turkey's ruling AK Party has slipped by 1.6 points from June's election to 39.3 percent, a survey from pollster Gezici showed on Monday, casting doubt on the AKP's chances of forming a single-party government after a November 1 vote.
The center-right, Islamist-rooted AKP founded by President Tayyip Erdogan lost its single-party majority in June for the first time since coming to power in 2002, taking 40.9 percent of the vote.
After failing to secure a coalition, Prime Minister Ahmet Davutoglu has formed an interim cabinet ahead of the November re-run.
The survey of 5,000 people between September 12 and September 13 showed the biggest improvement was by the main opposition CHP at 28.1 percent, from 25 percent in June.
Support for the nationalist MHP was at 16.8 percent from 16.3 percent three months ago.
The pro-Kurdish HDP was at 13.5 percent, from 13.1 percent in June and still comfortably above the 10 percent threshold required to enter parliament.
The results of the Gezici survey were in marked contrast to a separate poll from Metropoll last week, which showed support for the AKP ticking higher, although still not enough for a single-party majority.