A Justice Ministry spokesman said an investigation had been launched into the incident.
"The weapon appeared to be a knife and there will be an investigation into how it was brought into the courthouse.''
According to Justice Ministry figures, about 7000 "potential weapons'' were confiscated by New Zealand court security staff during the 2011/12 financial year.
More than 1.3 million people were searched during the 12-month period.
Confiscated weapons included knuckledusters, a metal bar, dozens of knives, ammunition, a piece of wood with protruding nail and a ball and chain, Justice Ministry information showed.