A strong odour of faeces disrupted a key vote in Georgian parliament Thursday after opposition MPs splattered the plenary chamber with an unidentified substance.

Georgia's parliament speaker Archil Talakvadze, in televised remarks, accused the opposition of making a "chemical attack on the legislature", adding that the plenary session had been interrupted as a result.

Forensic experts in medical masks took samples of the air in the plenary hall, footage on national television showed. The session resumed afterwards, boycotted by the opposition.

Georgian parliament was Thursday set to vote for the appointment of 14 Supreme Court judges whom the opposition had denounced as "stooges" of the ruling Georgian Dream party.

Over the past few weeks opposition supporters have staged a series of mass rallies in Tbilisi after the ruling party voted down an electoral reform bill in mid-November.

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