THE Garda Commissioner has been notified after dramatic scenes outside the Dail forced two government senators to abandon their vehicles.
A combined demonstration against water charges and the Greek situation descended into chaos after Oireachtas members were abused as they tried to exit the premises.
Former justice minister Alan Shatter criticised the policing of the protest after he was blocked for several minutes as he attempted to enter Leinster House.
"My car was thumped and kicked by some protesters. It was a clear example of thuggery," he told the Herald.
But as the evening drew on, a large section of protesters staged a sit-in protest which caused traffic chaos.
There were dramatic scenes after two Labour senators - Mary Moran and Derek Landy - were forced to abandon their vehicles on Kildare Street.
"I have never experienced anything like this. It was totally disgraceful to see the gards attacked in that manner ," Ms Moran said.
At least one garda officer was injured and received medical treatment after she was hit by a traffic cone.
Meanwhile, the Committee for Procedure and Privileges (CPP) has formally requested that Garda Commissioner Nóirín O'Sullivan appear in Leinster House to explain the garda operation that was put in place.
TDs have been critical of the decision not to place railings around the entrance to Leinster House as is the norm during large protests.
Sources say senior gardai previously attended a CPP meeting and assured members that there would be no situation whereby TDs and senators were prevented from leaving or entering Leinster House.
The organisers said the protest was a response to the Government rushing further water charges legislation through the Dail this week.
Environment Minister Alan Kelly has introduced a number of amendments to the Environment Miscellaneous Provisions Bill.
These include setting up a database for the water conservation grant and the blocking of a house sale until water charges are paid.
The law, which is now being finalised, will also oblige local authority tenants to pay their water charges.