"Operation Bearclaw", a large amateur military simulation event, was held over the weekend at a farm on Coal Pit Rd.
Participants were given the scenario that private military contractors had been used in Afghanistan for security work, but there had been a revolt and the Euro Task Force was trying to quell it.
Organiser Deane Campbell said the exercise took the form of a sport called Airsoft, in which participants eliminated opponents using replica firearms.
The event, which saw about 100 people play skirmishes in two teams for about three hours, was intended to be as realistic as possible.
Men and women were inserted by helicopter, then given missions by radio and, using weapons such as grenades, gas propelled pyro packs, pistols and standard rifles, their mission was to eliminate the competition.
"It's not like the movies where there's just shooting. They also have to do a four-hour hike - they are committed and driven," Mr Campbell said.
"It's a bit of fun and there are prizes for different individuals ... We had a run in freezing conditions, but we had a great time."
About half of the participants had some sort of military experience and many were retired soldiers. Enthusiasts came from as far afield as Australia.
The team of private military contractors won outright on points.
Mr Campbell said while he hoped the event could become an annual fixture, it was a huge undertaking to organise.
He said it could not have been possible without the support of the local community, especially Bill Malcolm, for the use of his farm, Heliventures, New Zealand Defence Force, Oamaru Cadet Force, Oamaru police and the Waitaki District Council.