US-based rights body Human Rights Watch has accused the Georgian government of "crossing the line" in its crackdown on opposition protests last month.
The police response to the protests has been heavily criticised
The group said police had chased and beaten peaceful demonstrators and threatened and intimidated journalists.
Water cannon, rubber bullets and tear gas were used in November to disperse demonstrators calling for President Mikhail Saakashvili's resignation.
Mr Saakashvili briefly imposed a state of emergency before calling snap polls.
He faces opposition nominee Levan Gachechiladze in a presidential election on 5 January.
"The Georgian government crossed the line when police chased and beat peaceful demonstrators, and threatened and intimidated journalists," Holly Cartner of Human Rights Watch said.
The police crackdown on protesters on 7 November was "not legitimate", she said, and had "done serious damage to Georgia's reputation as a champion of human rights".
Mr Saakashvili says he wants elections to provide a fresh start
The criticism of the government was echoed by Brussels-based conflict-resolution consultancy, International Crisis Group.
In a statement released on Wednesday, the group said the government's "repressive and disproportionate" response had shocked countries in the West that had "viewed Georgia as a beacon of democracy in a region of illiberal regimes".
President Saakashvili, a US-educated lawyer, came to power after street protests in 2003, nicknamed the Rose Revolution.
His first term as president has seen Georgia strengthen its ties with Nato while relations with Moscow have soured.
Thousands of Georgians recently took part in rallies accusing Mr Saakashvili of corruption and authoritarianism.
The protests were the largest Georgia had seen since the Rose Revolution.
The demonstrations were eventually put down by police and a brief state of emergency was imposed.
The main opposition TV station, Imedi, was also forced off the airwaves, accused of inciting the protesters.
It has since begun broadcasting again.
A Georgian interior ministry spokesman told the AFP news agency the authorities were investigating alleged "abuse of power" in the police response to the demonstrations.
At the time, Mr Saakashvili accused Russian agents of backing opposition protests and said the emergency measures were needed to thwart a "coup" attempt.