South Africa is ranked 123 out of 144 countries on the Global Peace Index 2009, it was announced on Tuesday.
"South Africa has fallen fifteen places compared with GPI 2008," the Institute for Economics and Peace said in a statement.
It obtained unfavourable scores for, in order of most impact: the level of violent crime, number of homicides, ease of access to weapons, level of organised internal conflict, perceptions of criminality, respect for human rights and likelihood of violent demonstrations.
Favourable indicators were: the number of heavy weapons, volume of major conventional weapons exported and imported, number of displaced people, estimated number of deaths from organised external conflict, potential for terrorist acts, military expenditure, number of armed services personnel and United Nations funding.
In the African region, South Africa is ranked 21 out of 31 countries, behind Botswana, Malawi and Gabon, ranked top three, and ahead of countries including Zimbabwe, the Democratic Republic of the Congo and Somalia.
New Zealand tops the overall rankings as the world's most peaceful country, followed by Denmark and Norway.
Western or Central European democracies account for 14 of the top 20 rankings. All five Scandinavian countries are in the top 10.
The United States is ranked 83, registering a "significant negative" for jailing a higher proportion of its population than any other country in the index.
The country ranked least at peace is Iraq -- for the third year running.
Also at the bottom end of the rankings are Afghanistan and Somalia.
Madagascar has fallen the most -- 30 rankings -- amid political instability and violent demonstrations. Bosnia Herzegovina has risen the most -- up 23 rankings from 73rd position last year.
The Global Peace Index was started three years ago by Australian technology entrepreneur and philanthropist Steve Killelea.
It forms part of the Institute for Economics and Peace, a global think-tank on the relationship between economics, business and peace, and is calculated on the institute's behalf by the Economist Intelligence Unit and its network of country analysts.
"The world has become slightly less peaceful in the past year after the intensification of violent conflict in some countries and as the dramatic global economic downturn took its toll," the index found.
A separate study, released with the index, on the economic impact of violence found that lost peace costs US4.8 trillion (about R55 trillion) a year, and that peace is a significant factor in the creation of wealth.
"... The causes of peace are becoming apparent and the net economic benefit to humanity is substantial," said Killelea.
"Peace does have an economic value apart from the very real humanitarian values associated with it," he said.
Anglo American chairman Mark Moody-Stuart, who also chairs the Global United Nations Compact said: "The business community can and does benefit significantly from non violent environments, but perhaps business must now consider how sound, transparent and ethical business practices can play a larger role in bringing out about stability and peace."
The index's supporters include Nobel Laureates Archbishop Emeritus Desmond Tutu, Professor Joseph Stiglitz and former United Nations secretary-general Kofi Annan, and businessman Richard Branson.
"People need to understand the structure and attitudes that create peace and start to build them into their societies," said Killelea.
"Peace lies at the centre of being able to manage the many and varied challenges facing humanity, simply because peace creates the optimum environment in which the other activities that contribute to human growth can take place," he said. - Sapa