Justice Minister David Ford's constituency office has been targeted by arsonists.
Scorch damage was caused to the outside of the premises in Glengormley after liquid was poured on the building and set alight.
Mr Ford said: "This is a despicable attack on an office which provides an important service to the whole community. This was a cowardly and cynical attack.
"Those seeking to cause damage and fear will not prevent us from getting on with our role of serving the public.
"This is an attack on democracy. Incidents like this make us all even more determined to protect peace and ensure we have a society free from violence and division."
SDLP justice spokesman Alban Maginness said: "This is an attack on democracy and is completely and utterly reprehensible.
"The villains responsible must be caught, brought before our courts and punished for this wanton act of destruction.
"There are no winners following this attack; there is just disruption to a constituency service for people in Glengormley."