The Environment Minister Alan Kelly says whoever sent a suspicious package to his office is a "scumbag".
The package, containing white powder and a threatening note, was discovered by a woman working at the Nenagh office on Friday morning.
It was later declared a hoax.
Speaking to Tipp FM, Minister Kelly said he is used to threats, but he hit out at those responsible for targeting his staff.
He said: "The Gardaí know my movements, all day, every day, I go through them all the time so I'm used to that, but this is a different level.
"The lads inside my office, to be subjected to something like that - where their safety is an issue now - is a level which I've never encountered before.
"Whoever sent this is a scumbag, it's as simple as that."