The chancellor George Osborne has paved the way for an expected rise in Britain's IMF contributions in the wake of the renewed crisis in Greece and the wider eurozone.

The chancellor is in Cannes for the ongoing G20 summit, which has been dominated by the chaos triggered by the Greek government's wavering on whether to hold a referendum on the bailout agreed two weeks ago to keep the country in the single currency.

The Greek government - which spent much of yesterday teetering on the brink of collapse - was told by the European Commission that if it left the Euro then it would also have to leave the EU.

George Osborne is expected to announce that Britain's contribution to the IMF would be increasing, but refused to give even a general figure of how much it would rise by.

"We have to make sure that the international institutions of the world like the IMF, that help countries across the globe, are ready to withstand global shocks," he told BBC Radio 4. "This summit, unlike some of the others, has not been pre-cooked. We haven't come here with a communique that has already been drafted.

"I am not suggesting that Britain should contribute disproportionately, in other words out of kilter with the kind of contributions it has made in the past to supporting the IMF and the international institutions. I'm not saying that Britain should go out on a limb. Britain will be acting in concert with other countries around the world."

Britain's contribution to the IMF has already doubled in the past six months. In June the Treasury announced that it would rise from £10.5billion to £19.7billion. In addition Britain has pumped nearly £13bn into eurozone countries in the form of loans to Ireland and Portugal and existing IMF commitments to Greece.

Osborne will be conscious of the 80 Tory Euro Rebels who voted against the government whip in the Commons last week over an EU referendum. Many of those MPs have already warned against any British IMF money being sunk into further bailouts for Eurozone countries, and dozens more Tory MPs have reservations about writing a blank cheque to the IMF only for the money to be used to prop up the Euro.

Pundits at Cannes believe the French and German governments are pushing major nations not in the Eurozone to substantially increase their IMF contributions to avoid the Greek crisis spreading to other Eurozone nations, particularly Italy. Any repeat of the Greek-style debt crisis in Italy would have severe consequences for the future of the Euro, as well as threaten the global banking system as a whole.