The leaders of the council -- which is a union of six opposition parties -- announced the results of a primary and a public opinion poll at a congress held in Tbilisi's Chess Palace on April 9.
With more than 12,000 voters taking part in the poll, National Council leaders said 51.9 percent voted for Zviad Dzidziguri, the leader of Conservative Party. He will be the council's candidate for mayor.
Runner-up Koba Davitashvili, who leads the People's Party, received 48.1 percent of the poll and will be the council's candidate to chair the city council.
Other candidates for the 50-seat city council were also selected through the opinion poll.
Zurab Noghaideli, leader of the Movement For A Just Georgia, declared at the congress that the National Council will run a thorough and "intense" electoral campaign.
The local elections will be held on May 30, along with some by-elections to fill empty parliamentary seats. A total of 36 parties and movements have applied to take part in the elections.
Incumbent Mayor Gigi Ugulava, an ally of President Mikheil Saakashvili, is the favorite. The vote is also being contested by top opposition leader Irakli Alasania, head of the opposition Our Georgia-Free Democrats.