Georgian police used tear gas to disperse protesters on Tuesday in central Tbilisi after parliament gave its initial backing to a draft law on "foreign agents" which critics say represents an authoritarian shift in the South Caucasus country.

The law, backed by the ruling Georgian Dream party, would require any organisations receiving more than 20% of their funding from overseas to register as "foreign agents", or face substantial fines.

Critics have said it is reminiscent of a 2012 Russian law that has since been used to crack down on dissent.

Georgian television showed protesters angrily remonstrating with police armed with riot shields who then used tear gas. Local television said police also used water cannon to disperse the protesters.

Earlier, the law had comfortably passed its first parliamentary reading, Georgian media outlets reported.

Some of the protesters gathered outside the parliament building carried European Union and U.S. flags, and shouted: "No to the Russian law".

Speaking in Berlin earlier on Tuesday, Georgian Prime Minister Giorgi Garibashvili reaffirmed his support for the law, saying the proposed provisions on foreign agents met "European and global standards".

"The future of our country doesn't belong to, and will not belong to, foreign agents and servants of foreign countries," he said.