There is no "immediate prospect" of repatriating powers from the European Union, William Hague has said.
The Foreign Secretary insisted he had "not gone soft and will never go soft on Europe", but he said the Government's priority had to be ensuring the eurozone is stabilised without damaging Britain's interests.
"The repatriation of powers, which is something I support by the way, is not an immediate prospect because no countries are proposing widespread treaty change," Mr Hague told the BBC's Andrew Marr show.
"That may change, but at the moment, that is not what they are proposing... Britain's opportunity to these kinds of issues comes if there is a major change in the European treaties and the other nations need our co-operation in order to do that."
He went on: "Our priority is for the eurozone to be stabilised and at the same time to protect the British national interest."
Chancellor George Osborne warned eurozone leaders on Saturday that they need to take "impressive" action to get a grip on the crisis sweeping the global economy.
The EU summit in Brussels next weekend will be a crucial moment in finding a "solution" to the problems, he said.
Speaking after a meeting of G20 finance ministers, Mr Osborne also indicated that Britain would be open to providing more money to the International Monetary Fund - but not if it is only used to prop up the struggling single currency area.
The eurozone has set up a European financial stability facility (EFSF) worth 440 billion euro (Â£384 billion).
However many economists believe a fund of around two trillion euro (Â£1.75 trillion) will be needed to fully reassure anxious investors that banks would survive defaults by heavily indebted countries such as Greece and Italy.