Rising instances of conflict and poverty have propelled a 20% increase in the number of international migrants over the space of four years, according to a major report from the UN showing the scale of global migration.

According to the UN’s International Labour Organization the total number of people who left their home country in search of work, to join family, or to flee conflicts and persecution increased to 277 million last year from 232 million in 2013.

In what is the most authoritative attempt so far to chronicle the growing number of people on the move across the planet, the ILO said rising levels of inequality in many parts of the world were having a significant impact, which governments could not ignore by adopting populist policies.

Manuela Tomei, the director of the ILO’s conditions of work and equality department, told the Guardian that migration was becoming a “defining feature” of the modern world and that the issues it posed could not be solved by individual nations acting alone.

“The way in which migration and labour migration in particular has been dealt with until now is a recipe for disaster. There is a need to place it seriously and highly on the global agenda,” she said.

The report comes as support rises for rightwing populist parties in several major economies around the world, fuelled by anti-immigrant sentiment and the hollowing out of the middle class from weak wage growth and austerity policies used after the global financial crisis.

Tomei said that scapegoating migrants and imposing tougher border controls was not the answer to solving the socioeconomic and political pressures posed by rising levels of migration, adding that the ILO’s work was carried out to bring facts to a debate that often relies on perceptions and misinformation.

“If you’re saying there are hordes of migrants that are invading us, and the numbers are unrelated to reality, this may trigger a syndrome of anxiety and insecurity and the response would be ‘let’s keep them out’,” she said.

Some of the increase in the number of international migrants is down to a rising world population, which is on track to hit 8 billion in 2023, and the better quality of data used to make the ILO’s estimates. However, the organisation did single out the impact from rising inequality and a growing number of conflicts around the world, such as the war in Syria, as well as droughts and other environmental issues.

Of the 277 million, 19 million are refugees, 234 million are over the age of 15, and 164 million are workers, according to the ILO estimates, with a particular rise for people moving to improve their economic life chances.

Migrant workers were found to overwhelmingly move to wealthier nations, with three-fifths of all migrants concentrated in three regions: North America (23%), south and west Europe (24%) and the Arab states (14%).

Arab countries had the largest percentage of migrant workers as a proportion of their overall workforce and had seen big increases in arrivals in recent years as more workers moved to work in major cities like Dubai, Riyadh and Doha, which are experiencing building booms.

Across nine out of 11 regions analysed by the ILO, the percentage of migrants in work was higher than that of the local population, showing that when people move abroad they tend to do so for work, rather than other reasons.

Migration due to rising inequality comes after the World Bank estimated that almost half of the world’s population – 3.4 billion people – live on less than $5.50 (£4.30) a day, and struggle to meet basic needs.

Tomei said: “The widening of income inequalities within countries, and among countries, is a very, very important factor in explaining the reason why so many millions of people are moving across borders to find better working and living conditions.”