Outgoing president Salome Zourabichvili, a pro-EU opponent of the ruling party, said in a defiant speech to supporters outside the presidential palace that she was leaving the residence but that Kavelashvili had no legitimacy as president, which is a mostly ceremonial position.
"I will come out of here and be with you," she said on Sunday.
Salome Zourabichvili said she was leaving the presidential palace and "taking legitimacy with me". (AP PHOTO)
"I am taking legitimacy with me, I am taking the flag with me, I am taking your trust with me," she said, before walking out of the palace to mingle with her supporters.
Zourabichvili says Kavelashvili, a hardline critic of the West, was not duly picked, as the MPs who chose him were elected in an October parliamentary election that she says was marked by fraud.
Georgia's opposition parties support her.
The inauguration came a day after thousands demonstrated in Tbilisi and other cities to demand new parliamentary elections and denounce the government as illegitimate.
The Georgian Dream ruling party and the country's election commission say the October election was free and fair.
The presidential stand-off is seen as a watershed moment in Georgia, a country of 3.7 million that had until recently been regarded as among the most democratic and pro-Western of the former Soviet states.
Kavelashvili is a loyalist of Bidzina Ivanishvili, a reclusive billionaire ex-prime minister who is widely seen as Georgia's de facto leader.
On Friday, the US imposed sanctions on Ivanishvili, saying he was spearheading Georgia's current anti-Western and pro-Russian turn.
Kavelashvili, a former professional football player who briefly played for Manchester City, has accused Western intelligence agencies of plotting to drive Georgia into war with neighbouring Russia.
President Mikheil Kavelashvili accuses the West of plotting to drive Georgia into war with Russia. (AP PHOTO)
"The Georgian people have always understood that peace is the main prerequisite for survival and development," he said after being sworn in on Sunday.
Protesters outside parliament held up red cards in a mocking reference to Kavelashvili's athletic career.
Georgian Dream received almost 54 per cent of the official vote in October's election.
Local and international election monitors have said the vote was marked by violations, and Western countries have called for an investigation.
Zourabichvili is backed by the country's four main pro-EU opposition parties, which have boycotted parliament since the election.
They say she will remain the legitimate president until fresh elections are held.
The confrontation comes amid a month of protests sparked by Georgian Dream's suspension of EU accession talks until 2028, abruptly halting a longstanding national goal of joining the bloc that is written into the country's constitution.
The move touched off widespread anger among Georgians, who polls show are firmly pro-EU, and prompted a police crackdown, with more than 400 people, including senior opposition leaders, detained.
Zourabichvili has accused Georgian Dream of deliberately sinking Georgia's EU hopes and instead moving towards Russia, from which Georgia gained independence in 1991.
with DPA
