Police said the victim had opened a parcel bomb.

The explosion happened only metres away from the office of the minister, Michalis Chryssohoidis, who was unhurt.

Greek Prime Minister George Papandreou said the bombing was a terrorist attack. So far no group has said it was beind the bomb.

The blast was so powerful that some in the heavily guarded building thought it had been struck by an earthquake.

The victim was later identified as Giorgos Vassilakis, a 50-year-old father of two.