Gardaí are investigating "criminal damage" at the constituency office of Fine Gael TD Michelle Mulherin in Ballina, Co Mayo.
A broken window at the front of the office was reported shortly after 7pm this evening.
It is understood that flammable material had been thrown into the building on John Street.
When gardaí arrived at the office, they found a small fire had broken out.
One unit from Mayo County Fire Service attended the scene and brought the blaze under control.
Gardaí say the office sustained "minimal damage", mostly as a result of smoke from the fire.
In a statement tonight, Ms Mulherin said that gardaí are investigating an incident at her office.
She added: "Thankfully nobody was injured.
"I await the outcome of the garda investigation and will be making no further comment at this stage."
The TD faced some controversy earlier this week when it emerged that she made calls totalling €2,000 to an individual mobile phone number in Kenya.
However, she has said that none of the calls she made from her Dáil office to Kenya were personal.
