The prime ministers of Britain and Spain called for a "real reform of the eurozone" that makes growth and free trade a priority, in a joint newspaper column published Friday ahead of their talks in Madrid.
Spanish Prime Minister Mariano Rajoy and his British counterpart David Cameron also said they hoped a free trade agreement between the European Union and the United States would be finalised "this year".
"We agree that a real reform of the eurozone without that does not harm the rights of members of the European Union who are not part of the common currency is needed," the two leaders wrote in the column published in daily business newspaper Expansion.
Britain is a member of the European Union but is not one of the 19 nations that has adopted the euro single currency.
The European Union was built to promote peace and democracy following the Second World War but after the global financial crisis of 2008 "growth must now be the main goal of the EU", the two leaders said.
Rajoy, in power since 2010, and Cameron, in power since 2011, said the economies of their two nations were on "the edge of the abyss" five years ago due to high debt levels and weak competitiveness, but have returned to growth because they "cleaned up" their public finances.
"We must ensure that the EU is much more competitive and that the momentum of national structural reforms is applied again at the EU level," they wrote.
They called on the EU to better unify its single market, criticising the "many internal barriers" that remain and prevent companies from offering their services throughout the territory.
"We need a 'passport', especially in the areas of engineering and accounting, that would allow one to operate in all European countries once one has received the green light to do so in one of them," the two leaders said.
The also urged the EU to better connect its energy market.
But the immediate emphasis should be on successfully wrapping up a free trade deal with the United States.
"Our main priority must be to achieve the most ambitious bilateral agreement in history: a EU-US free trade agreement would benefit companies across the continent, from services companies in Spain to automobile manufacturers in Britain," they wrote.
"We must make sure it is possible this year," they added.
The European Union and the United States launched negotiations in July 2013 to create a free trade agreement, the Transatlantic Trade and Investment Partnership (TTIP).
This agreement would create the world's biggest free trade area but opponents argue it would mainly benefit multinational firms.
Rajoy and Cameron will hold talks in Madrid later on Friday with a press conference set for 1400 GMT.