KPMG was commissioned by the Iraqi Governing Council to investigate the scandal-hit fund, but the work was halted after Paul Bremmer, the head of the US-led Coalition Provisional Authority, said it could not be paid for out of CAP funds without a proper tender process.

A twin-track process emerged as a result. The governing council has confirmed KPMG as the investigator, but the provisional authority still has its tender procedure underway.

The position leaves the firm unclear as to where it stands and the governing council deeply frustrated.

Bremmer's office has come under intense pressure in recent days to clear the way for KPMG to restart its work.

Claude Hankes-Drielsma, appointed by the Iraqi finance minister Ahmed Chalabi to advise on the oil for food programme, has written to Paul Bremmer saying the delays are deeply 'disturbing'.

'It is always important for investigations of this nature to be carried out as quickly as possible. This is to prevent those under investigation from destroying or altering records, or from silencing witnesses,' he wrote.

The oil for food programme came under fire after it was reported that it was dogged by widespread corruption.

The Coalition Provisional Authority was not available for comment.