Eight billionaires own the same wealth between them as the 3.6 billion people who make up the poorer half of the world's population, according to a new report published by Oxfam.
The Oxfam report said the concentration of wealth at the top among just eight men is holding back the process of ending global poverty.
The report comes before political and business leaders meet tomorrow at the World Economic Forum in Davos, Switzerland.
The report, "An Economy for the 99%", says the richest 1% has owned more wealth than the other 99% combined.
Oxfam said tax avoidance by corporations and wealthy individuals is contributing to inequality with the poorest losing out.
The report said those tax revenues are critical for funding the policies and services that can fight inequality including infrastructure, health and education.
Oxfam Ireland is urging the Government to introduce new mechanisms to increase tax transparency and stop tax avoidance by multinational corporations.
The Chief Executive of Oxfam Ireland said the report's findings highlighted the existence of an extreme level of global inequality.
Speaking to RTÉ's Morning Ireland, Jim Clarken said it was now a more serious concern than climate change and conflict.
He added that people were being locked into extreme poverty and it is very hard for them to find a way out.
This inequality, he said, was holding back entire economies but it could be corrected.
"Global leaders are very aware now of the fact that if stark inequality continues at this level, it has a global economic impact," said Mr Clarken. "This is not something that is inevitable. This is something that is a result of policy choices, and can be changed with the right kinds of policy choices."