Police were called to government Minister Gerry Brownlee's local office this morning after a window was found smashed and fuel was thrown inside.
Staff discovered the damage at the office on Greers Rd in Ilam this morning. A window was smashed at some stage between Saturday afternoon and Monday morning.
Fuel had been thrown inside but there was no indication someone had tried to light it, Detective Greg Murray says.
Investigators are at the scene.
If you have any information, police would like to hear from you on (03) 363 7400 or anonymously through Crimestoppers on 0800 555 111.