NZDF's Southern Katipo war games exercises around the top of the South Island.

Political instability in the troubled – if fictitious – South Pacific nation of Becara at the top of New Zealand's South Island has been squashed by a Kiwi-led global intervention force.

Over the past five weeks Becara – which takes in Marlborough, Kaikōura, Tasman, Nelson and Buller regions stretching from Greymouth to Kaikōura – has been a training ground for soldiers from Tonga, Papua New Guinea, Fiji, Chile, Brunei, Malaysia and Timor Leste joined by small contingents from Australia, Canada, the United States, France and Britain.

Now in its fourth – and most ambitious – edition the Southern Katipo military exercise is held every two years and this year involved 3000 people, 13 countries, six helicopters, 17 planes, five ships and more than 100 vehicles.

NZDF Australian soldiers from A Company, 1st Battalion, The Royal Australian Regiment form up for the assault covered by a New Zealand LAV during a Black Katipo operation at Greymouth's Omoto Racecourse last week.

Southern Katipo began at the start of October and ends on Saturday and was a continuation of the 2015 scenario, in which New Zealand deployed a military contingent to lead a multi-national combined joint taskforce to help restore law and order after ethnic rivalries exploded into violence in Becara.

READ MORE:

* Watch NZ Defence Force and locals step up to save orca 'Lucy'

* Southern Katipo helps Defence Force prepare for the next major disaster

* Kaikōura residents freak out at military presence in Southern Katipo exercise

* Southern Katipo exercise descends on top of the south

* Two tonnes of food every three days keeps base Katipo ticking

The taskforce conducted stability, support and humanitarian operations, including the evacuation of those internally displaced by the violence.

NZDF Grey District Mayor Tony Kokshoorn talks with the Commanding Officer of the Second First Battalion, Royal New Zealand Infantry Regiment. Kokshoorn was rescued during a scenario at Inangahua during the exercise.

Exercise director, Lieutenant Colonel Martin Dransfield, said this year higher threat levels were used to create more challenging training environments across the spectrum of operations.

The longer duration – up from three weeks to five – and expanded area was a "large leap forward" that had tested the Defence Force's resilience in every area from communications to logistics.

"In the context of this operation in the southwest Pacific we feel confident the New Zealand Defence Force could and would lead a joint operation task force into any situation we face," Dransfield said.

The operation's success owed much to the support and involvement of local communities, Dransfield said.

That alliance between the military and locals was highlighted last week when defence personnel and locals banded together to save an orca that had been stranded for more than 24 hours at Marfells Beach, near Seddon.

Southern Katipo land component commander Brigadier Mike Shapland said when they got the call for help each personnel member raised their hand to assist.

NZDF The crew commander covers assaulting troops from the turret of a light armoured vehicle during an operation at Omoto Racecourse in Greymouth during last week's multinational Southern Katipo military and disaster relief exercise.

There was a "smorgasbord of military" helping out, including engineers and stewards, and Shapland said it was a great way to help the community out and finish up the exercise.

Alliances had also been strengthened with success in operating for the first time with countries like Timor Leste and Chile contingents as well as involving the Ministry of Foreign Affairs and Trade, and the Ministry of Health, in the operation for longer and in bigger numbers.

PIPPA BROWN/STUFF Exercise director Lieutenant Colonel Martin Dransfield said the boosted length and scale of Black Katipo 2017 had tested the Defence Force's resilience across everything from logistics to communications.

Other organisations supporting the exercise included Customs, the Ministry for Primary Industries, the NZ Transport Authority, Immigration New Zealand, district health boards, Red Cross and St John New Zealand.

Communication difficulties and the resulting friction with non-governmental organisations in the shift from a disaster scenario to a conflict one was one issue that cropped up and was an area were networks needed to be joined up.

But Dransfield said the operation had been a success.

ANNA MUIR/STUFF New Zealand Defence Force personnel digging a trench on to help re-float a stranded orca on a beach near Seddon during the exercise.

"There's an appetite to do it again but for longer and with more complex scenarios . . . it keeps everyone match fit."