A study surveying people in 65 countries has found happiness is on the rise globally, with Fiji leading the way.

The research by polling organisation WIN/Gallup found 70 per cent of the 64,000 respondents were content with their life, a 10 per cent increase from last year.

The group's annual global End of Year survey explores the outlook, expectations, views and beliefs of people across the globe.

This year, researchers asked a sample of people from each country to rate their happiness, and whether the coming year would be better or worse than the last.

Respondents were also asked about their country's economic prosperity, and whether they would go to war for their country.

Fiji was by far the happiest country in the world: 93 per cent of respondents said that they were either happy or very happy.

The Pacific nation was followed, at some distance, by Finland, where 80 per cent said they were content.

Iraq the world's unhappiest nation

The world's unhappiest country was Iraq, where approximately one in three people said that they were either unhappy or very unhappy.

Overall, 70 per cent of survey respondents said that they were happy, up 10 per cent from 2013.

Just six per cent declared themselves to be unhappy, compared to last year's 12 per cent.

And despite Fijians expressing such happiness, the Oceania region was among the least content, with 14 per cent responding that they were either unhappy or very unhappy.

Africa appeared to be the happiest region in 2014 with 83 per cent of those surveyed across the continent being content, followed by Asia with 77 per cent.

Africa and Asia were also the most optimistic about next year.

Nigeria proved to be the most positive country about 2015 with 85 per cent of respondents thinking it will be better, whereas Lebanon was most pessimistic with more than half believing it will be worse.

Nigeria also overwhelmingly believed 2015 would be a year of economic prosperity, while western Europeans were pessimistic about their economies.

Italians least willing to go to war for their country

In the year that has marked the centenary of the start of World War I, 60 per cent of global respondents said they would be willing to take up arms for their country, while 27 per cent would not.

Western Europeans were the most reticent, with one quarter saying they would fight.

In contrast, around 77 per cent of people from the Arab countries of Middle East and North Africa said they would be willing to fight for their countries.

Despite being widely recognised for their neutrality, 39 per cent of people from Switzerland said they would be prepared to go to war for their country.

It was the Italians who proved to be least willing to bear arms for their country with 68 per cent revealing they would refuse to do so.

Jean-Marc Leger, the president of WIN/Gallup International Association, said happiness showed no sign of waning across the globe.

"This year's survey also highlights that people across the world are increasingly optimistic and believe that 2015 is set to be a good year," he said.