The accounts held by the Coalition Provisional Authority in Iraq should be made public to prevent a larger financial "black hole" emerging, a leading charity has said.

A study by Christian Aid has found that while $5 billion dollars have been allocated to the rebuilding of post-war Iraq, only $1 billion can be accounted for.

The missing billions will double by the end of the year without the accounts being made public, the charity warns.

A United Nations resolution was passed last week calling for international contributions of money and troops.

The funds will be managed by the World Bank and the UN, although Christian Aid argues that concern over the missing funding held by the United States will fuel suspicion that large amounts of money are being made by the American firms awarded contracts for the reconstruction.

"The British government must use its position of second in command of the CPA to demand full disclosure of this money and its proper allocation in the future," said Roger Riddell, Christian Aid's international director.

"This is Iraqi money. The people of Iraq must know where it is going and it should be used for the benefit of all the country's people - particularly the poorest."

An International Advisory and Monitoring Board was supposed to be established after another UN resolution was passed earlier this year, charged with overseeing the accounts, however this has failed to materialise.