The front gates of Leinster House were blocked with a cement mixer truck today as members returned after their lengthy summer recess.
The words "Toxic Bank Anglo" were written in red letters along the barrel of the truck, which was driven up to the guarded gates on Kildare Street at 7.15am.
A 41-year-old man was arrested at the scene and is being detained at Pearse Street garda station.
No one was injured in the incident.
A garda spokesman said the suspect is being held under section 4 of the Criminal Justice Act 1984. He can be held for 24 hours.
Gardai and a recovery crew were attempting to remove the truck, which was immobilised and was blocking one lane of Kildare Street.
It is understood specialist equipment would be needed to move the vehicle.
In April, a cement mixer truck, with similar wording on it, was abandoned outside a branch of the bank on Forster Street, Galway. The cabin was locked and the engine left running.
Onlookers said all the windows on the cement truck were covered in metal grids and had been smashed, with the doors of the cabin welded shut.
It appeared some electric cables were cut before the driver escaped through a hatch on the roof.
Fine Gael TD Fergus O'Dowd revealed that at least one garda on duty at the gates of the Dail had to jump out of the way of the truck.
"If it had been later in the morning, staff could have been killed, public could have been killed," said the opposition politician, who was first at the scene.
"I think it's a very serious incident and I think it's an appalling vista to be doing your job as a garda or usher in Dail Eireann and to be seriously injured."
The incident was sparked by controversial plans by the Government to plough more than €20m into State-owned Anglo Irish Bank.
Its former chairman, Sean FitzPatrick, was declared bankrupt in July - owing the institution about €110m.
The ex-banker, who resigned from Anglo in December 2008 following a loans scandal, is also at the centre of a massive fraud and corporate mismanagement investigation by the Garda and watchdog Paul Appleby, the director of corporate enforcement.
Mr O'Dowd said politicians would not be nervous after today's incident, which he believed was a one-off.
The registration plate on the cement mixer spelt out the word "bankrupt".
A spokesman for the Dail confirmed the truck was towed from outside the Kildare Street gates of Leinster House at around 9.30am.
"Access arrangements are now back to normal and there will be no disruption to the proceedings or workings of the Houses Oireachtas today," he added.
Meanwhile Congress, the umbrella trade union, is planning a protest at the Dail later today to mark the return of Government TDs after the summer recess.