The Government will try to seize back powers from Brussels when the "right moment" arises, the Foreign Secretary William Hague said today.
He said the eurozone had become a "burning building with no exits" but insisted the UK had to help "quench the flames" as our interests were too closely tied to its future.
In a speech to the Conservative Party conference in Manchester, Mr Hague also said Britain could be "immensely proud" of its part in overthrowing Libyan dictator Colonel Muammar Gaddafi.
Prime Minister David Cameron had the "steel and the humanity" to call for a no-fly zone over Libya in its "hour of crisis", he said.
The coalition's new National Security Council had met nearly 60 times to discuss the situation in Libya, Mr Hague said, as he claimed ministers are now trying to rebuild the UK's diplomatic service following years of neglect under Labour.
But Mr Hague concentrated his speech on the UK's role in Europe.
He told activists: "It is now acknowledged that when we said that joining the euro would be a disaster for Britain, we were right. When we said that Labour should not have let us get sucked in to the eurozone bailouts, we were right, and now thanks to David Cameron European bailouts for Greece will not call on the British taxpayer. When we said that the costs of the EU budget were out of control we were right, and now we have had unprecedented success in bringing it under control.
"And when we said that no more areas of power should go to the EU we were right. And now thanks to the European Union Act 2011, by law that cannot happen without a referendum. And we are just as right that the EU has more power in our national life than it should, and I believe as strongly as I ever have that when the right moments come this party should set out to reduce it."
He added: "Fourteen years ago I predicted that the eurozone would become a burning building with no exits. But because the eurozone countries are our friends and neighbours, and because our prosperity and financial stability is tied with theirs, we must now support them in quenching the flames. But we will never make the mistake of thinking that anyone else can be relied upon to stand up for the interests of Britain."