Grenade-shaped paperweights and gas lighters are among the items that have triggered dozens of bomb squad callouts around the country this year.
And although the replica grenades do not hold the same threat as a real one, authorities say it is still vital for people to stay vigilant when it comes to such items.
The New Zealand Defence Force has released new information about some of the call-outs its bomb disposal squad have gone to in the last few months.
In the last second quarter of the year, the Explosive Ordnance Disposal team - known as E Squadron - have been called out to 40 incidents sparked by grenade novelty items purchased online or through the international mail system.
The same time last year, there had been 32 callouts.
Colonel Rian McKinstry said: "At first glance, replica grenades look like the real thing. So although they are not potentially dangerous, they have caused concern at the mail centre.
"When you are unsure, ring for help and prevent potential harm to yourselves and others.
"It's best to be safe rather than sorry,'' he said.
Special equipment, including what is dubbed the robot, is used at many of the incidents.
In another recent call-out, the squad was required at a mail centre when an X-ray machine picked up a package that appeared to have an improvised explosive device inside.
The parcel was addressed to a university student.
"When our bomb disposal team inspected the item, they were able to identify it as a prank. But the mail centre staff did the right thing by having it checked,'' McKinstry said.
The majority of the callouts this year, in the second quarter, have been in Auckland, with 12 incidents.
There were four in Wellington and five in Christchurch in that time.
The E Squadron also regularly helps laboratories and universities around the country to dispose of chemical stocks that have become unstable.