Police fires a water cannon against protesters demanding the government's resignation and early parliamentary polls outside the parliament in Tbilisi. (AFP)

Police in Georgia on Tuesday arrested protesters and used water cannon to disperse demonstrators who pressed ahead with anti-government rallies despite a new police crackdown.

Opposition supporters have staged a series of rallies in the capital Tbilisi in recent weeks urging the government to resign and calling for new legislative elections, with up to 20,000 people taking to the streets on Monday.

Braving sub-zero temperatures, hundreds of protesters stayed outside parliament overnight, blocking all four entrances and threatening to prevent lawmakers from entering the building.

On Tuesday morning, riot police used water cannon to disperse the crowd and made new arrests.

The interior ministry said in a statement that 28 protesters were arrested and several were injured.

Opposition leaders said the use of police force would only galvanise protest movement and vowed to hold “permanent protests” until their demands are met.

The latest demonstrations broke out two weeks ago after the ruling party voted down legislation to hold parliamentary elections next year under a new proportional voting system.

Opposition parties have called the rallies after forming a rare united front against the ruling Georgian Dream party led by oligarch Bidzina Ivanishvili.

The 63-year-old Ivanishvili is widely believed to be more powerful than Prime Minister Giorgi Gakharia and is accused by critics of orchestrating the bill’s failure.

Tina Bokuchava, one of the leaders of Georgia’s main opposition force, the United National Movement, said the ruling party’s foundation was based on police violence.

“Ivanishvili’s regime has feet of clay,” Bokuchava told AFP.

“Protest movement is gaining momentum and will achieve its goal — we will force Ivanishvili to introduce fair electoral system,” she added.

A fresh protest rally will be held on Tuesday evening, she said.

Protesters say the current voting system unfairly favours the ruling party.

Georgian Dream won nearly 77 percent of seats in the 2016 parliamentary election despite garnering only 48.7 percent of the vote.

Georgian Dream has ruled out early polls.

On Monday, it also rejected the opposition’s compromise proposal of legislative amendments that would create a level playing field for all political parties in the tiny Black Sea nation.

Last week, riot police also used water cannon to disperse protesters and arrested several dozen people outside parliament.

In a joint statement last week, the embassies of the United States and European Union criticised Georgian Dream’s failure to introduce the electoral reform and expressed solidarity with the protesters.

Ivanishvili had promised “large-scale political reform” following a summer of protests that saw 240 people injured in a police crackdown.

Two protesters including a teenage girl lost an eye during those protests.

In power since 2012, the ruling party has seen its popularity plummet amid widespread discontent over economic stagnation and perceived backsliding on its commitment to democracy.

Critics accuse Ivanishvili of persecuting political opponents, suffocating critical media, and creating a corrupt political system where his private interests dominate government decision-making.