The Liberal Democrats have warned a cash injection by five central banks will not ease the global credit crunch.
Lib Dem economics spokesman Vince Cable joined Gordon Brown in welcoming the £54 billion loan package, which will be made available to global money markets.
But Mr Cable warned: "Nobody should be under any illusions that this money will solve the problems in the global economy.
"It is merely adding a spot of oil to a machine that is grinding to a halt."
Mr Cable pointed out the proposals amount to just over £50 billion to prop up the entire world, compared to the £30 billion pumped in to save Northern Rock.