Dominique Strauss-Kahn, the IMF's managing director, told the Financial Times that change would not happen overnight and world powers meeting in Washington on November 15 would not create a new international treaty.

'Expectations should not be oversold,' Mr Strauss-Kahn told the paper.

'Things are not going to change overnight. Bretton Woods took two years to prepare. A lot of people are talking about Bretton Woods II.

'The words sound nice but we are not going to create a new international treaty.'

The G20 summit will discuss reform of the IMF, set up as part of the Bretton Woods agreement on international financial management signed in 1944.

The European Union has called for an overhaul of the IMF with French President Nicolas Sarkozy, whose country holds the EU's rotating presidency, saying: 'We want to change the rules of the game.'

The US, though, has been more lukewarm on the possibility of radical change.

Mr Strauss-Kahn also voiced caution about the idea of a global early warning system to prevent future world economic crisis, backed by British Prime Minister Gordon Brown among others.

'I have heard contradictory things about it,' he said.

'I don't think you can have a mechanical system with red lights and green lights and, sometimes country by country, the light goes from green to red.'

The IMF chief backed the need for input from US president-elect Barack Obama in the process.

'If the summit sets up working groups, they will operate as a bridge to the new administration,' he said. 'In this respect, it would be nonsense to work without the input of the new administration.'

Mr Obama's spokesman said on Friday that he would not attend the G20 summit next week. -- AFP