"Let me tell you that it is puzzling that you seem to delight in the difficulties of the euro area," Barroso told the British Tories, adding that this was in stark contrast with the position taken by Prime Minister David Cameron.
Barroso was taking aim especially at Conservative MEP Martin Callanan, who has repeatedly criticised bank bailouts as wasting taxpayers' money and talked in favour of eurozone exits for some countries.
According to Callanan, the alternative strategy is for the eurozone to reduce in size so that some countries have the ability to devalue their way back to relative competitiveness.
Barroso retorted that "there is a consensus, including among those states outside of the euro area, on the need to strengthen the euro area. It would be a complete mistake to try to divide the euro area from the rest of the EU."
"Those who know European history know how negative was the role of prejudices of one part of Europe over another,” he said, adding that the European project was made precisely to avoid these divisions of the past.
About 100 Conservative lawmakers wrote to Cameron last week calling for a legal commitment to holding a referendum in the next Parliament.
Cameron has rejected an immediate referendum but signalled he is open to a vote on renegotiating British ties to the union
As the debt-strapped eurozone eyes greater fiscal, banking and possibly even political integration, Cameron is under growing pressure from the rebellious right wing of his own party to give Britons a vote on whether they wish to remain inside the EU or to downgrade their relationship with Brussels.
London's place in the common market would be at stake in such a vote as - potentially - would London's status as a regional financial hub.
Britain's relationship with the EU has been a toxic issue for the Conservative party in the past, helping topple previous party leaders, and is a headache for Cameron, who has made a string of policy U-turns in recent weeks that have emboldened eurosceptics in his own party to press their demands.