With a decision to expand its anti-crisis "firewall", the euro zone has thrown the ball firmly back into the court of other economic powerhouses who pledged more cash for the International Monetary Fund (IMF) if Europe stumped up first.

After providing loans to help debt-wracked countries, IMF head Christine Lagarde has asked members to give her $500 billion in extra funds for possible future euro zone bailouts.

The euro zone clinched a deal it claimed was worth more than $1 trillion, even though 300 billion euros of that was in loans already pledged.

In fact, they raised the maximum lending capacity of their bailout pools to 700 billion euros ($934 billion), on a temporary basis, from 500 billion euros. European officials nevertheless judged they had done enough to unlock funds from other G20 members.

And although the boost to the new "firewall" was far less ambitious than many wanted, Lagarde seemed satisfied ahead of the crunch April 20-22 IMF meeting where the issue of fresh lending for the IMF will be discussed.

The deal "will strengthen the European firewall and support the IMF's efforts to increase resources for the benefit of all our members," she said.