Ministry of Justice figures reveal 214 items deemed offensive such as credit card-sized, fixed-blade and flick knives, screwdrivers, scissors and daggers were seized in Whangarei's Bank St courthouse between January 2013 and August this year.
The Northern Advocate understands most of the items were confiscated from people summonsed for jury service.
Under the Crimes Act people can be charged with possessing an offensive weapon in a public place, including courts. No one has been charged for that offence in Northland courts and seized weapons were normally returned to their owners.
Metal detectors were first introduced in Whangarei courts in 2006 and an X-ray machine about three years ago.
They are used from 8.30am to 10.30am daily and between 100 and 200 people use the court on busy days, usually Monday and Wednesday.
There were no security screenings in Kaitaia, Kaikohe and Dargaville courts before September last year.
Only eight offensive weapons have been taken from owners in Kaikohe court and five in Kaitaia so far. None were found on people entering Dargavillle court.
Michael Hubbard, deputy director of courts and judicial security, said if an offensive weapon was found, court security officers had the power to permanently seize the items and detain the person under the Court Security Act.
Police were then called.
"Sometimes items inadvertently brought to the courthouse, such as cutlery, screwdrivers and multitools, are taken into temporary custody and returned to the owners as they leave the court," he said.
Mr Hubbard said knives were the most common offensive weapon detected and during the past two years there had been a rise in the number of people entering court buildings with concealed blades such as credit card knives - knives made from plastic, that fold down to the size of a credit card.
An offensive weapon is defined in the Crimes Act as something that is either made, altered or intended to cause bodily harm.
Court security officers operate under statutory powers granted under the Court Security Act, which include the ability to search and remove people from courts, and detain them for contempt under judicial order or for specific offences. They may use force while detaining people.