The former head of the United Nations' oil-for-food programme has quit the UN, lashing out at Secretary General Kofi Annan for "sacrificing" him.
Mr Sevan said he had was a victim of political expediency
Benon Sevan's announcement on Sunday came a day before a third report on the scandal-plagued programme is published.
It is expected to accuse Mr Sevan of receiving cash in return for allocating Iraqi oil contracts in the mid-1990s.
The oil-for-food programme allowed Saddam Hussein to sell limited amounts of oil to buy humanitarian goods.
Mr Sevan's lawyers have already said the report will falsely accuse him of receiving cash kick-backs for helping a company obtain lucrative oil contracts under the scheme.
Mr Sevan, a Nicosia-born Cypriot who had worked with the organisation for four decades, tendered his resignation in a letter addressed personally to Kofi Annan.
"I fully understand the pressure you are under [...] but sacrificing me for political expediency will never appease our critics or help you or the Organization," he wrote.
Mr Sevan was suspended in February. Despite retiring last year, he was retained on the UN payroll on a nominal annual salary of $1 for the duration of the investigation.
The report is the third in a series produced by an independent inquiry committee established by the UN, under the leadership of Paul Volcker, the former US Federal Reserve chairman.
A separate inquiry is being conducted by a committee of the US Senate.
In his letter Mr Sevan insisted he was innocent of any charges that would be made against him.
"The charges are false and you, who have known me all these years, should know they are false," he wrote.
In February, the independent panel investigating the allegations of corruption in the oil-for-food scandal had said that Mr Sevan had received payments of cash as well as oil allocations.
Mr Sevan said the real oil-for-food scandal was the way the programme was misrepresented by those who were against the UN.
He said he was disappointed by Mr Annan's "failure to defend the historic achievements of the oil-for-food programme."