At least 15 people have been arrested during scuffles with police as protesters blocked the entry to the annual Defence Industry Association Forum in Wellington.
Around 75 people, one dressed as the grim reaper while others held up John Key masks, locked arms to prevent delegates from attending the two-day defence gathering at the TSB Arena today.
Violent scuffles were sparked as delegates tried to enter the stadium with protesters swarming them while chanting "blood on your hands".
Anglican Bishop of Wellington Justin Duckworth was among those attending the demonstration.
The protest comes as 200 defence-related companies, including international defence and technology giant Lockheed Martin, gather for the forum in the lead-up to the Defence White Paper 2015.
One of the organisers of the demonstration, Arthur Price, said their protest had been a success despite the arrests.
"They're not welcome to meet in Wellington," he told NZ Newswire.
"There's a lot of people standing around outside because of our blockage so it's absolutely a success."
Protesters had promised a peaceful demonstration, however scuffles broke out with police as officers made arrests.
But many inside were not perturbed by demonstrators, despite loud banging on the arena's walls, as delegates including Defence Industry Association chairman Bernie Diver gave speeches.
He said the meeting wasn't just about weapons and was an important part of the economy.
"NZ Defence expenditure is approximately 2500 full time jobs, generating a conservative $125 million in wages and $60 million in profits," he said.
"Companies from apparel to food service, property and facilities management through to personal safety and protection equipment are represented."