Mayoral contests in the four largest cities likely will need runoffs after the vote, overshadowed by the arrest on Friday of exiled former president Mikheil Saakashvili.
Members of Georgia's ruling party were in festive mood after early results suggested it had secured major victories in this weekend's local elections that are seen as a major test of the government.
The Central Elections Commission said on Sunday that tallies from about 39% of precincts showed the ruling Georgian Dream party with about 49% of the overall vote, followed by the main opposition party United National Movement (UNM), with 31%. Several other parties were in single digits.
But despite the ruling party's apparent lead nationwide in the in ex-Soviet republic, mayoral contests in the four largest cities likely will need runoffs.
The election has been overshadowed by the arrest on Friday of exiled former President Mikheil Saakashvili, also the founder of UNM, upon his return to the country in a bid to galvanise opposition to Georgian Dream.
"I want to congratulate you all. My dear people it is a big honour for us to win for the eighth time. I want to congratulate you and each member of the Georgian Dream," said Prime Minister Irakli Gharibashvili as the early results came in.
But Georgia's opposition had reason to celebrate too. They called for an early general election after claiming victory in Tbilisi, although the results in the capital were still too close to call on Sunday morning.
The cities of Batumi, Kutaisi and Rustavi also appeared to be heading for runoffs because no candidate was registering an absolute majority of votes.
"The victory of the opposition especially in Tbilisi will pave the way to the snap early parliamentary elections in Georgia," said Nika Melia, UNM Chairman and candidate for mayor in Tbilisi.
"We’ll have the snap early parliamentary elections in Georgia and through this victory the former president of Georgia Mikheil Saakashvili, of course, will be released from prison."
Ahead of the election, the former president made an appeal from jail, calling on supporters to protest and "save Georgia" by turning out to vote.
His return to the country on Friday in a bid to bolster the opposition was his first visit since his departure in 2014.
Saakashvili was given a six-year prison term in his absence, in a case he says is politically motivated. The current president says she will not offer him a pardon.
The political situation in Georgia has significantly deteriorated since the European Union helped broker an agreement between the two main parties last April, designed to put an end to the country's political crisis.