David Cameron has called for speedy action to deal with the crisis in the eurozone on the eve of talks with German chancellor Angela Merkel.
But the Prime Minister cautioned against holding Germany solely responsible for delays in dealing with the long-running debt crisis.
The talks in Berlin take place against the backdrop of uncertainty in Spain, whose economy minister has been forced to deny that his country is about to seek a bailout of its banks.
Mr Cameron and Ms Merkel will use the talks to prepare the way for the G20 talks in Mexico later this month, when the eurozone crisis will be top of the agenda in the wake of re-run elections in Greece on June 17.
Ms Merkel has been blamed in some quarters for refusing to throw Germany's massive financial muscle behind ailing euro members such as Greece and Spain by signing up to "eurobonds", which would spread the burden of debt among the 17 single currency members.
But Mr Cameron said: "I don't think it's right to try to lay all the responsibility on one person. It is everyone in the eurozone and throughout the EU - we all need to do the right things to help ease this crisis."
The Prime Minister was speaking in Oslo alongside his Norwegian counterpart Jens Stoltenberg, who will join Mr Cameron and Ms Merkel in Berlin. Despite not being part of the EU, Mr Stoltenberg said Norway was heavily affected by the crisis in the single currency, which has hit many of its most important trade partners.
At a press conference in the garden of Mr Stoltenberg's residence, Mr Cameron said: "Speed is of the essence. Every day that the European economies are stagnant are days when opportunities are lost, wealth is lost, jobs can be lost. So we need to get our economies moving.
"Clearly the eurozone crisis is the biggest threat to the world economy today. It is the biggest challenge that we all face. It is the thing we have to fix, to sort out, to help restore growth right across the world economy."
On Tuesday, Mr Cameron spoke to US President Barack Obama, who agreed on the need for "an immediate plan" to resolve the eurozone crisis.