An Air New Zealand flight to Christchurch was delayed when an unchecked rifle was discovered in the cargo hold.
Activist Max Tweedie was on board flight NZ547 as it prepared to take off from Auckland Airport on Thursday afternoon.
"We were sitting on the tarmac, we'd pretty much all boarded the flight," he told Newshub. "Then all of a sudden a member of the ground crew came on board and six people were taken off the flight. We kind of heard from the inflight service manager that something was happening."
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As he and his fellow passengers sat in confusion, the captain made an alarming announcement via the overhead speaker: a man had a rifle in his luggage that hadn't gone through the necessary checks.
"We were all kind of looking around at each other once it was announced," Tweedie said. "Obviously we're all on a bit of high alert."
The owner of the rifle was offloaded and the group travelling with him voluntarily chose to be offloaded as well. Getting all six people and their luggage off the aircraft took a bit of time, delaying the flight by about half an hour.
In the wake of the Christchurch shooting, Tweedie said he felt safer seeing how vigilant Air NZ was about checking for firearms.
"The captain was very clear with passengers what was going on and the process that was being followed, so we didn't feel like we'd been left in the dark about what was happening. It was all very straightforward."
He said the experience had him feeling "a bit on edge" but he didn't feel unsafe.
"Perhaps it's a reminder of the heightened tension around the country at the moment."
Air NZ confirmed that Aviation Security had requested a passenger's checked bag be removed from the baggage hold of flight NZ547.
"The passenger who owns the bag had already boarded and was completely compliant when asked to disembark," the airline said. "They have been rebooked to continue their journey on a later flight.
"At no time did anyone attempt to board the flight carrying a firearm."
Aviation Security said precautionary checks were carried out and it was determined the rifle was being lawfully transported.
"While Avsec regrets the inconvenience to passengers, public safety is its number one priority."
NZME reports several Government employees were on board the delayed flight, including official from the Department of Internal Affairs travelling to Christchurch for Friday's National Remembrance Service.
New Zealand remains on a high terror alert and security has been ramped up around the country after 50 people were killed in two mosques two weeks ago.