A sound bomb exploded on Saturday near a hospital in the Upper Egyptian governorate of Qena, minutes before the health minister was due to arrive, according to Al-Ahram's Arabic news website.
Health Minister Adel Adawy's scheduled appearance was for a ceremony announcing the opening of the hospital to the public.
The bomb was thrown from outside the hospital fence and into the grounds, Al-Ahram's reporter in Qena, Mahmoud El-Desouky, told Ahram Online.
The explosion produced a loud blast of noise that caused minor injuries to a hospital employee but no damages to the building, according to eyewitnesses who spoke with Al-Ahram.
The governorate's security director, Mohamed Kamal, told Al-Ahram that the explosion came from a metal pipe filled with gunpowder. .
No one was injured, Kamal said.
The health minister proceeded with the opening of the hospital following an examination by explosives experts.
Adawy was instated in the cabinet of interim Prime Minister Ibrahim Mahlab on 1 March.
Egypt has been hit by a spate of deadly bombings, mainly targeting security forces, since the ouster of Islamist president Mohamed Morsi in July of last year.