The workshop will teach tactics for non-violent direct action, such as linking arms and sitting down to block an entrance. The action could get more creative, with street theatre and costumes.
Auckland Peace Action hopes Whanganui people will help blockade the New Zealand Defence Industry Association Expo in Wellington on October 10-11.
The protesters will need courage and determination, Ms Morse said.
"The idea is to stand strong, but not be aggressive. We are not there to be pushed around but we are certainly not there to push other people around."
Association chairman Scott Arrell didn't mention protest in his online invitation, only saying he was "confident that the participants' experience will not be unduly impacted by others".
The expo is annual and usually in Wellington, the home of the country's Defence Ministry. It will be in the Westpac Stadium and attract 169 companies and 550 delegates.
The New Zealand military will show its gear, and see what else it can buy with the extra $20 billion allocated last year by the National-led government. There will be weapons and equipment on display, information shared and deals made.
Ms Morse said New Zealand had more involvement in arms than could be expected by a country with no direct military threat. Both National and Labour governments have wanted to develop that kind of industry here.
The peace group is opposed to the global arms trade, saying the companies that manufacture weapons have an incentive to encourage war.
"Every time a bullet is fired, or a missile launched, they make a profit. This is fundamentally wrong - no one should profit from wars or disasters."
