That means the coalition would be able to help bail out countries such as Greece by increasing its IMF contributions without fear of being defeated in the Commons by an alliance of Eurosceptic Tory backbenchers and Labour MPs.
Alexander said: “We have two sorts of money that we give to the IMF. There’s a £20bn ceiling for each, so there’s a maximum of £40bn that we can make available to the IMF.
“Currently only about £5bn of that is actually in use, so we have the capacity to go up to that £40bn ceiling without a vote in Parliament.”
Labour, which has said IMF resources should not be used to bail out countries that have structural problems, hit out at Alexander.
Chris Leslie, Labour’s shadow Treasury minister, said: “Extra resources for the IMF must be subject to the normal parliamentary scrutiny, in order to ensure we safeguard the best interests of British taxpayers.”