106 Kiwi troops are based at the Taji military camp in Iraq to train Iraqi soldiers.

New Zealand ranks as the fourth most peaceful country in the world, but globally inequality has widened and peace has declined.

According to the recently released Global Peace Index, political instability and the impact of terrorism were the main factors of deterioration. Conflicts intensifying in the Middle East and North Africa regions were particular contributors.

So is New Zealand doing enough? Green Party global affairs spokesperson Kennedy Graham wasn't convinced.

KHALIL ASHAWI Conflicts in the middle east have contributed to a lower global peace score. Here a woman in Syria runs holding a walkie-talkie towards a damaged site after an airstrike on the rebel-controlled area of Maaret al-Numan town in Idlib province in May.

He said the Defence White Paper released this week drew an "opaque line" between respecting UN security authorisation for violence and reserving the right for targeted interventions.

READ MORE: Defence White Paper: Government unveils $20b defence plan for new planes, boats and cyber security

"On top of that you note that we are doing far less in respect to UN peacekeeping in terms of troop contribution than we used to in the past.

MAARTEN HOLL/ FAIRFAX NZ Green MP Dr Kennedy Graham said an International Law Index or a Conflict Prevention Index would be more useful.

"Although [the report] shows an increase in UN peacekeeping, certainly financially, I think New Zealand's starting to get left behind in support for UN peacekeeping and I think that's a major policy area we need to turn around.

"There is a bit of a trend away from support for UN peacekeeping and toward US-led coalitions and that begs the question how legal and legitimate those undertakings are.

"The 2003 invasion of Iraq was the obvious worse example of that, New Zealand did not get engaged but Australia did."

In 2011, 458 New Zealand Defence Force troops and more than 75 police officers were serving in 19 UN-led or UN-endorsed peacekeeping missions, according to the national encyclopaedia.

In 2016, New Zealand had 175 troops overseas. Of those, 16 were in UN-based peacekeeping missions.

Graham said New Zealand had kept up the finance side, but the numbers of bodies on the ground had decreased.

"There's a whole developing apparatus to make peacemaking and peacekeeping more effective mission by mission [led by the UN] and New Zealand's really missing in action in that respect."

He noted the top peaceful countries were "small, and strategically not that important", therefore an International Law Index or a Conflict Prevention Index would be more useful.

Defence Minister Gerry Brownlee and Foreign Affairs Minister Murray McCully were not available for comment.

Panama, Thailand and Sri Lanka showed greatest improvements in peace, whereas Yemen, Ukraine and Turkey suffered the greatest deteriorations.

The Index looked at 23 qualitative and quantitative indicators in three areas: safety and security in a society, the extent of domestic or international conflict, and the degree of militarisation.

THE COST OF DESTRUCTION AND CONFLICT

The Index also highlighted the huge cost to countries with conflict zones, estimating the economic impact of violence on the global economy totalled $13.6 trillion or 13.3 per cent of gross world product this year.

That was equivalent to 11 times the size of global foreign direct investment.

Taking into account the past decade of peace scores trickling downward, researchers put the cost over the long-term at $137 trillion.

The Index calculated expenditure on two types of costs, direct and indirect.

Examples of direct costs included medical costs for victims of violent crime, capital destruction from violent conflict and costs associated with the security and judicial systems.

Indirect costs included lost wages or productivity from crime due to physical and emotional trauma.

Refugees and displaced persons had risen dramatically over the last decade, doubling to approximately 60 million people between 2007 and 2016, nearly 1 per cent of the world's population.