The bill would require organisations receiving more than 20% of their funding from abroad to register as being agents of foreign influence. It is likely to pass in a parliament controlled by the ruling party and its allies.

Its approval by a parliamentary committee on Monday provoked major protests, with more than 5,000 people facing off against riot police and water cannon to oppose a bill that the EU has said is "incompatible" with its values.

Georgian critics have compared it to Russian legislation used by the Kremlin to crack down on dissent - a potent charge in the South Caucasus country, where Russia is unpopular for its support of the breakaway regions of Abkhazia and South Ossetia. Russia defeated Georgia in a short war in 2008.

Several hundred protesters demonstrated outside parliament on Tuesday afternoon shouting slogans against what they call "the Russian law" as police continued to seal entrances to the Soviet-built complex in central Tbilisi.

Civil society groups have called for another round of mass protests on Tuesday evening.

During the debate on the bill, Archil Talakvadze, a senior MP representing the Georgian Dream ruling party, said: "This law defends democracy in our country from any foreign interference."

In response, Tina Bokuchava, parliamentary leader of the United National Movement opposition party said: "Recall this law, once and for all! There is no place in Georgia for a Russian law. Europe is the choice of the Georgian people."

The bill must pass three readings in parliament, and will then likely face a fourth vote to override a veto by President Salome Zourabichvili, a Georgian Dream critic who opposes the bill but whose powers are mostly ceremonial.

Western countries including the United States, Britain and Germany have urged Georgia not to pass the bill.

Georgia's government, which has faced accusations of authoritarianism and pro-Russian leanings, says the law is needed to promote transparency and combat "pseudo-liberal values" imposed by foreigners.

The ruling Georgian Dream party unexpectedly reintroduced the bill earlier in April, 13 months after abandoning an earlier attempt to pass the law amid protests.

Outside parliament on Monday, protesters chanted slogans against "the Russian law", and shouted "Russians! Russians!" at police and ruling party MPs.

Inside the chamber, opposition MP Aleko Elisashvili was shown on television punching Mamuka Mdinaradze, faction leader of Georgian Dream, as he spoke from the despatch box.

Protesters against the bill told Reuters that they saw Georgia's future membership of the EU, which is overwhelmingly popular in the country of 3.7 million, as being on the line.

"I don't like that the government is trying to suppress NGOs and put some labels on them as if they are foreign agents," said Luka Tsulaia, a 32-year-old computer programmer.

"It's about maintaining independence and also maintaining the laws so that we can integrate with the European Union better."

(Reporting by Felix Light; Editing by Mark Trevelyan and Andrew Heavens)

By Felix Light