A survey of more than 800 business leaders in the UK, France, Italy, Spain and Germany found a majority in each country believe debt levels are unsustainable.
Concern was greatest in the UK and Italy, where more than 70 per cent backed the need for change.
Six in 10 business leaders in both Italy and Spain also admitted they would struggle to repay their own debts if there was a new downturn.
Meanwhile, with France and Germany heading to the polls later this year, a majority of business leader in all five countries also branded nationalist and populist movements a cause for concern.
Dan Healy, head of research at FTI Consulting said: “Brexit being triggered might be the least of the EU’s challenges in 2017.”