Published Monday, 12 May 2014
The viable device, which had been packed into a milk churn with a timer attached, was discovered in a car with a NI registration in Lucan at about 9pm on Saturday.
Gardaí evacuated the hotel while the army bomb squad made it safe.
UTV understands the bomb may have been destined for Northern Ireland.
The man in his 50s, who was detained on Sunday, can be questioned for up to 72 hours.
A garda spokesperson said: "Gardaí at Lucan investigating the discovery of a suspect device, which was discovered in the car park of a hotel on 10 May, have arrested a man.
"He is detained at Lucan Garda Station under Section 30 of the Offences Against the State Act, 1939.
"He may be detained for up to 72 hours."
© UTV News